Fix constraint_name type in create_primary_key

The constraint name in create_primary_key should be optional, but for batch operations is is required according to the type annotations

### Description
Changed the type annotation to `Optional[str]`

### Checklist
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This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [X] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #1452
Pull-request: #1452
Pull-request-sha: 8afb2bf

Change-Id: Ic7bbbbfda85dafccdf44c73a6233140aa7e96a2d

alembic/operations/base.py

@@ -1771,7 +1771,7 @@ def create_index(
             ...
 
         def create_primary_key(
-            self, constraint_name: str, columns: List[str]
+            self, constraint_name: Optional[str], columns: List[str]
         ) -> None:
             """Issue a "create primary key" instruction using the
             current batch migration context.

alembic/operations/ops.py

@@ -349,7 +349,7 @@ def create_primary_key(
     def batch_create_primary_key(
         cls,
         operations: BatchOperations,
-        constraint_name: str,
+        constraint_name: Optional[str],
         columns: List[str],
     ) -> None:
         """Issue a "create primary key" instruction using the

setup.cfg

@@ -84,7 +84,7 @@ where = tests
 enable-extensions = G
 # E203 is due to https://github.com/PyCQA/pycodestyle/issues/373
 ignore =
-    A003,
+    A003,A005
     D,
     E203,E305,E704,E711,E712,E721,E722,E741,
     N801,N802,N806,