fix: add missing shell property to container scan action

Author: bilals12

container-scan/action.yaml

@@ -86,6 +86,7 @@ runs:
           echo "Error: Scan results file (results.stdout) does not exist."
           exit 1
         fi
+      shell: bash
 
     - name: Format Results for PR
       run: |
@@ -95,6 +96,7 @@ runs:
         cat results.stdout >> pr-results.md
         echo "</pre>" >> pr-results.md
         echo "</details>" >> pr-results.md
+      shell: bash
 
     - name: Check for Previous Report Comment
       id: find-comment