Add missing quote

Author: jonsimantov

.github/workflows/integration_tests.yml

@@ -417,7 +417,7 @@ jobs:
           echo "ta/**" >> .gitignore
           # Re-include these subdirectories, which CAN be cleaned.
           echo "!ta/*/*/CMakeFiles" >> .gitignore
-          echo "!ta/*/*/external >> .gitignore
+          echo "!ta/*/*/external" >> .gitignore
           echo "!ta/*/*/bin" >> .gitignore
           git clean -fd
           echo After cleanup: $(du -skh)