ci: fix merge workflow

Author: methane

.github/workflows/update.yml

@@ -100,7 +100,7 @@ jobs:
 
       - name: Merge overwriting on stable release branch
         run: |
-          pomerge --from "${{ env.CPYTHON_BRANCH }}/**/*.po" --to "${{ matrix.branch }}/**/*.po"
+          pomerge --from "${{ env.CPYTHON_BRANCH }}"/**/*.po --to "${{ matrix.branch }}"/**/*.po
 
       - name: Wrap catalog message files
         run: |