change some old references to TF for the import check

Author: sfmig

.github/workflows/test_include_guard.yaml

@@ -1,5 +1,5 @@
-name: Test Tensorflow include guards
-# These tests check that the include guards checking for tensorflow's availability
+name: Test Keras include guards
+# These tests check that the include guards checking for Keras availability
 # behave as expected on ubuntu and macOS.
 
 on:
@@ -9,7 +9,7 @@ on:
       - main
 
 jobs:
-  tensorflow_guards:
+  keras_guards:
     name: Test include guards
     strategy:
       matrix:

cellfinder/__init__.py

@@ -12,7 +12,7 @@
 except PackageNotFoundError as e:
     raise PackageNotFoundError(
         f"cellfinder tools cannot be invoked without Keras. "
-        f"Please install tensorflow into your environment to use cellfinder tools. "
+        f"Please install Keras into your environment to use cellfinder tools. "
         f"For more information, please see "
         f"https://github.com/brainglobe/brainglobe-meta#readme."
     ) from e