Update branch name from master to main in GH action workflow (#1516)

JAVA-5608

Author: jyemin

.github/workflows/release.yml

@@ -78,12 +78,12 @@ jobs:
           exit 1
 
       # For non-patch releases (A.B.C where C == 0), we expect the release to
-      # be triggered from master or the A.B.x maintenance branch. This includes
+      # be triggered from main or the A.B.x maintenance branch. This includes
       # pre-releases for any non-patch releases, e.g. 5.2.0-beta1
       - name: "Fail if non-patch release is created from wrong release branch"
-        if: ${{ endsWith(env.RELEASE_VERSION_WITHOUT_SUFFIX, '.0') && env.RELEASE_BRANCH != github.ref_name && github.ref_name != 'master' }}
+        if: ${{ endsWith(env.RELEASE_VERSION_WITHOUT_SUFFIX, '.0') && env.RELEASE_BRANCH != github.ref_name && github.ref_name != 'main' }}
         run: |
-          echo '❌ Release failed due to branch mismatch: expected ${{ inputs.version }} to be released from ${{ env.RELEASE_BRANCH }} or master, got ${{ github.ref_name }}' >> $GITHUB_STEP_SUMMARY
+          echo '❌ Release failed due to branch mismatch: expected ${{ inputs.version }} to be released from ${{ env.RELEASE_BRANCH }} or main, got ${{ github.ref_name }}' >> $GITHUB_STEP_SUMMARY
           exit 1
 
       # Set commit author information to the user that triggered the release workflow