chore: revert owlbot main branch templates (#186)

Author: dandhlee

owlbot.py

@@ -51,43 +51,3 @@
 
 s.shell.run(["nox", "-s", "blacken"], hide_output=False)
 
-# ----------------------------------------------------------------------------
-# Main Branch migration
-# ----------------------------------------------------------------------------
-
-s.replace(
- "*.rst",
- "master",
- "main"
-)
-
-s.replace(
- "CONTRIBUTING.rst",
- "kubernetes/community/blob/main",
- "kubernetes/community/blob/master"
-)
-
-s.replace(
- "docs/*",
- "master",
- "main"
-)
-
-s.replace(
- "docs/conf.py",
- "main_doc",
- "root_doc"
-)
-
-s.replace(
- ".kokoro/*",
- "master",
- "main"
-)
-
-s.replace(
- "README.rst",
- "google-cloud-python/blob/main/README.rst",
- "google-cloud-python/blob/master/README.rst"
-)
-