Fix crowdin upload branch name

Since we adapted the branching structure of the main opencast
repository we do not use main anymore. This patch adapts the
run command from the same workflow in the mian repo.

Author: Arnei

.github/workflows/crowdin-upload-keys.yml

@@ -26,4 +26,4 @@ jobs:
       env:
         CROWDIN_TOKEN: ${{ secrets.CROWDIN_TOKEN }}
       run: |
-        crowdin upload sources --config .crowdin.yaml -b main
+        crowdin upload sources --config .crowdin.yaml -b "${GITHUB_REF##*/}"