Update RH_BRANCH to main

Author: jtpio

.github/workflows/test.yml

@@ -75,7 +75,7 @@ jobs:
         env:
           GITHUB_ACCESS_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           RH_REPOSITORY: jupyter-server/jupyter_releaser
-          RH_BRANCH: master
+          RH_BRANCH: main
           RH_SINCE: v0.3.0
           RH_UNTIL: v0.4.0
         run: |