Fix remote cache miss

In some cases, the hermetic python toolchain would generate .pyc files
when being used, resulting in a remote cache miss. This commit excludes
generated files from the "files" filegroup to resolve this issue

python/repositories.bzl

@@ -142,6 +142,7 @@ filegroup(
         ],
         exclude = [
             "**/* *", # Bazel does not support spaces in file names.
+            "**/__pycache__/**",
         ],
     ),
 )