Pin github CI TENSORFLOW_VERSION to 2.9.0.rc1

Author: bileschi

.github/workflows/ci.yml

@@ -32,7 +32,7 @@ env:
   BUILDTOOLS_VERSION: '3.0.0'
   BUILDIFIER_SHA256SUM: 'e92a6793c7134c5431c58fbc34700664f101e5c9b1c1fcd93b97978e8b7f88db'
   BUILDOZER_SHA256SUM: '3d58a0b6972e4535718cdd6c12778170ea7382de7c75bc3728f5719437ffb84d'
-  TENSORFLOW_VERSION: 'tf-nightly'
+  TENSORFLOW_VERSION: 'tensorflow==2.9.0rc1'
 
 jobs:
   build: