fix CI

.github/workflows/formal-verification.yml

@@ -42,7 +42,7 @@ jobs:
         run: |
           if [[ ${{ github.event_name }} = 'pull_request' ]];
           then
-            RESULT=$(git diff ${{ github.event.pull_request.head.sha }}..${{ github.event.pull_request.base.sha }} --name-only certora/specs/*.spec | while IFS= read -r file; do [[ -f $file ]] && basename "${file%.spec}"; done)
+            RESULT=$(git diff ${{ github.event.pull_request.head.sha }}..${{ github.event.pull_request.base.sha }} --name-only certora/specs/*.spec | while IFS= read -r file; do [[ -f $file ]] && basename "${file%.spec}"; done | tr "\n" " ")
           else
             RESULT='--all'
           fi