fix: regex update in compute-branch

Author: diogomatsubara

.github/workflows/merge-release-branch.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Compute branch
         id: compute-branch
         run: |
-          if [[ "${{ matrix.repo }}" =~ eclipse-zenoh\/zenoh(?:-(pico|cpp))? ]] ; then
+          if [[ "${{ matrix.repo }}" =~ eclipse-zenoh\/zenoh(-pico|-cpp)? ]] ; then
             echo "branch=release/${{ inputs.version }}" >> $GITHUB_OUTPUT
           else
             echo "branch=eclipse-zenoh-bot/post-release-${{ inputs.version }}" >> $GITHUB_OUTPUT