Prepare 0.21.2 release (#8593)

Co-authored-by: Matthew Treinish <mtreinish@kortar.org>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "qiskit-terra"
-version = "0.21.1"
+version = "0.21.2"
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

docs/conf.py

@@ -23,7 +23,7 @@
 # The short X.Y version
 version = "0.21"
 # The full version, including alpha/beta/rc tags
-release = "0.21.1"
+release = "0.21.2"
 
 extensions = [
     "sphinx.ext.napoleon",

qiskit/VERSION.txt

@@ -1 +1 @@
-0.21.1
+0.21.2

releasenotes/notes/backend_name_fix-175e12b5cf902f99.yaml

@@ -1,7 +1,6 @@
 ---
 fixes:
   - |
-    'aer_simulator_statevector_gpu' was not recognized correctly as statevector
-    method in some function when using GPU on Qiskit Aer.
-    This fix recognizes both 'aer_simulator_statevector' and
-    'aer_simulator_statevector_gpu' the backend is statevector.
+    ``aer_simulator_statevector_gpu`` will now be recognized correctly as statevector
+    method in some function when using Qiskit Aer's GPU simulators in :class:`.QuantumInstance`
+    and other algorithm runners.

releasenotes/notes/bugfix-ucgate-inverse-global_phase-c9655c13c22e5cf4.yaml

@@ -1,9 +1,5 @@
 ---
 fixes:
   - |
-    Fixes the :meth:`.UCGate.inverse` method which previously did not invert the
+    Fixed the :meth:`.UCGate.inverse` method which previously did not invert the
     global phase.
-  - |
-    Fixes the global phase problem of the isometry decomposition. Refer to
-    `#4687 <https://github.com/Qiskit/qiskit-terra/issues/4687>` for more
-    details.

releasenotes/notes/fix-evolvedop-to-instruction-c90c4f1aa6b4232a.yaml

@@ -1,18 +1,18 @@
 ---
 fixes:
   - |
-    Fix :meth:`~.EvolvedOp.to_instruction` which previously tried to create a 
+    Fix :meth:`~.EvolvedOp.to_instruction` which previously tried to create a
     :class:`~.UnitaryGate` without exponentiating the operator to evolve.
-    Since this operator is generally not unitary, this raised an error (and if 
+    Since this operator is generally not unitary, this raised an error (and if
     the operator would have been unitary by chance, it would not have been the expected result).
 
-    Now calling :meth:`~.EvolvedOp.to_instruction` correctly produces a gate 
+    Now calling :meth:`~.EvolvedOp.to_instruction` correctly produces a gate
     that implements the time evolution of the operator it holds::
 
       >>> from qiskit.opflow import EvolvedOp, X
       >>> op = EvolvedOp(0.5 * X)
       >>> op.to_instruction()
       Instruction(
-          name='unitary', num_qubits=1, num_clbits=0, 
+          name='unitary', num_qubits=1, num_clbits=0,
           params=[array([[0.87758256+0.j, 0.-0.47942554j], [0.-0.47942554j, 0.87758256+0.j]])]
       )

releasenotes/notes/fix-opflow-vector-to-circuit-fn-02cb3424269fa733.yaml

@@ -2,7 +2,7 @@
 fixes:
   - |
     Previously it was not possible to adjoint a :class:`.CircuitStateFn` that has been
-    constructed from a :class:`.VectorStateFn`. That's because the statevector has been 
+    constructed from a :class:`.VectorStateFn`. That's because the statevector has been
     converted to a circuit with the :class:`~qiskit.extensions.Initialize` instruction, which
     is not unitary. This problem is now fixed by instead using the :class:`.StatePreparation`
     instruction, which can be used since the state is assumed to start out in the all 0 state.

releasenotes/notes/fix-optimizer-settings-881585bfa8130cb7.yaml

@@ -2,7 +2,7 @@
 fixes:
   - |
     Fix a bug in the :class:`~.Optimizer` classes where re-constructing a new optimizer instance
-    from a previously exisiting :attr:`~.Optimizer.settings` reset both the new and previous 
+    from a previously exisiting :attr:`~.Optimizer.settings` reset both the new and previous
     optimizer settings to the defaults. This notably led to a bug if :class:`~.Optimizer` objects
     were send as input to Qiskit Runtime programs.
 

releasenotes/notes/fix-paramexpr-isreal-8d20348b4ce6cbe7.yaml

@@ -1,14 +1,13 @@
 ---
 fixes:
   - |
-    Fix a bug where a bound :class:`.ParameterExpression` was not identified as real 
+    Fixed a bug where a bound :class:`.ParameterExpression` was not identified as real
     if ``symengine`` was installed and the bound expression was not a plain ``1j``.
     For example::
-  
+
         from qiskit.circuit import Parameter
 
         x = Parameter("x")
         expr = 1j * x
         bound = expr.bind({x: 2})
         print(bound.is_real())  # used to be True, but is now False
-

releasenotes/notes/prepare-0.21.2-71dd32f64f50e853.yaml

@@ -0,0 +1,4 @@
+---
+prelude: >
+  Qiskit Terra 0.21.2 is a primarily a bugfix release, and also comes with
+  several improved documentation pages.

releasenotes/notes/taper-performance-6da355c04da5b648.yaml

@@ -1,8 +1,7 @@
 ---
 fixes:
   - |
-    Fixed :meth:`.Z2Symmetries.taper` support for running on larger problems
-    method. Previously, the :meth:`~.Z2Symmetries.taper` method would require
-    a large amount of memory which would typically cause failures for
-    larger problem. As a side effect of this fix the performance has
-    significantly improved.
+    Fixed support for running :meth:`.Z2Symmetries.taper` on larger problems.
+    Previously, the method would require a large amount of memory which would
+    typically cause failures for larger problem. As a side effect of this fix
+    the performance has significantly improved.

setup.py

@@ -51,7 +51,7 @@
 
 setup(
     name="qiskit-terra",
-    version="0.21.1",
+    version="0.21.2",
     description="Software for developing quantum computing programs",
     long_description=README,
     long_description_content_type="text/markdown",