Switch back to tf 2.12 as minimum version (keras-team#1934)

* Switch back to tf 2.12 as minimum version

* Update backend shim

* Handle multiplex directly in kpls

keras_cv/layers/preprocessing/base_image_augmentation_layer.py

@@ -12,8 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import keras
 import tensorflow as tf
-from keras.src import backend as keras_backend
+
+if hasattr(keras, "src"):
+    keras_backend = keras.src.backend
+else:
+    keras_backend = keras.backend
 
 from keras_cv import bounding_box
 from keras_cv.backend import keras
@@ -118,7 +123,7 @@ def augment_image(self, image, transformation):
     ```
 
     Note that since the randomness is also a common functionality, this layer
-    also includes a keras.backend.RandomGenerator, which can be used to
+    also includes a keras_backend.RandomGenerator, which can be used to
     produce the random numbers. The random number generator is stored in the
     `self._random_generator` attribute.
     """

keras_cv/layers/preprocessing/vectorized_base_image_augmentation_layer.py

@@ -12,8 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import keras
 import tensorflow as tf
-from keras.src import backend as keras_backend
+
+if hasattr(keras, "src"):
+    keras_backend = keras.src.backend
+else:
+    keras_backend = keras.backend
 
 from keras_cv import bounding_box
 from keras_cv.backend import keras
@@ -97,7 +102,7 @@ def __init__(self):
     ```
 
     Note that since the randomness is also a common functionality, this layer
-    also includes a keras.backend.RandomGenerator, which can be used to
+    also includes a keras_backend.RandomGenerator, which can be used to
     produce the random numbers. The random number generator is stored in the
     `self._random_generator` attribute.
     """

keras_cv/version_check.py

@@ -18,7 +18,7 @@
 import tensorflow as tf
 from packaging.version import parse
 
-MIN_VERSION = "2.13.0"
+MIN_VERSION = "2.12.0"
 
 
 def check_tf_version():

keras_cv/version_check_test.py

@@ -29,11 +29,11 @@ def cleanup_tf_version():
 
 
 def test_check_tf_version_error():
-    tf.__version__ = "2.12.0"
+    tf.__version__ = "2.11.0"
 
     with pytest.raises(
         RuntimeError,
-        match="Tensorflow package version needs to be at least 2.13.0",
+        match="Tensorflow package version needs to be at least 2.12.0",
     ):
         version_check.check_tf_version()