fix: Separate GHA and bash substitution (#356)

Author: Ryan Williams

.github/actions/update-gitops/action.yml

@@ -95,6 +95,7 @@ runs:
       if: inputs.CREATE_PR == 'true'
       working-directory: gitops
       run: |
-          BRANCH_NAME="deploy-${{ inputs.SERVICE_NAME }}-${{ inputs.IMAGE_TAG//:/- }}"
-          git push -u origin $BRANCH_NAME
+          BRANCH_NAME="deploy-${{ inputs.SERVICE_NAME }}-${{ inputs.IMAGE_TAG }}"
+          BRANCH_NAME=${BRANCH_NAME//:/-}
+          git push -u origin "$BRANCH_NAME"
           gh pr create --title "Update image tag for ${{ inputs.SERVICE_NAME }}" --body "Update image tag for ${{ inputs.SERVICE_NAME }}"