chore(deps): update dependency google-cloud-video-transcoder to v1.2.1 (GoogleCloudPlatform#7026)

Co-authored-by: Leah E. Cole <[email protected]>

Author: renovate-bot

media/transcoder/requirements.txt

@@ -1,3 +1,3 @@
 google-api-python-client==2.25.0
 grpcio==1.41.1
-google-cloud-video-transcoder==1.2.0
+google-cloud-video-transcoder==1.2.1