Fix: fix the error when multiple changed files were flattened to one line

Signed-off-by: Hanxi Zhang <[email protected]>

Author: hanxizh9910

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
           # For pushes to mainline or PRs targeting mainline, only build changed versions
           if [[ ("${{ github.event_name }}" == "push" && "${{ github.ref }}" == "refs/heads/mainline")]] ; then
             changed_files=$(git diff --name-only HEAD~1 HEAD)
-            if echo $changed_files | grep -qE "^(versions\.json|[0-9]+\.[0-9]+/|unstable/)"; then
+            if printf "%s\n" "$changed_files" | grep -qE "^(versions\.json|[0-9]+\.[0-9]+/|unstable/)"; then
               changed_versions=$(echo $changed_files | grep -oE "[0-9]+\.[0-9]+|unstable" | sort -u | tr '\n' '|' | sed 's/|$//')
               if [[ -n "$changed_versions" ]]; then
                 strategy=$(jq -c --arg versions "$changed_versions" '{"fail-fast": .["fail-fast"],"matrix":{"include":[ .matrix.include[]|select(.meta.entries[0].directory | test($versions))]}}' <<<"$strategy")