Update release branch script as main branch is now "main".

sampart · sampart · commit 6d413dd72327 · 2020-06-23T10:08:23.000+01:00
See https://github.com/github/dsp-code-scanning/issues/1457
diff --git a/.github/update-release-branch.py b/.github/update-release-branch.py
@@ -7,7 +7,7 @@
 
 # The branch being merged from.
 # This is the one that contains day-to-day development work.
-MASTER_BRANCH = 'master'
+MASTER_BRANCH = 'main'
 # The branch being merged into.
 # This is the release branch that users reference.
 LATEST_RELEASE_BRANCH = 'v1'
