ci: require rb-sys 0.9.126+ for Ruby 4 cross-gems

Author: kateinoigakukun

.github/workflows/build-gems.yml

@@ -54,6 +54,13 @@ jobs:
             echo "Failed to detect rb-sys version from Cargo.lock" >&2
             exit 1
           fi
+
+          # Ruby 4.0 cross-compilation support requires newer rb-sys/rake-compiler-dock.
+          min_version="0.9.126"
+          if [ "$(printf '%s\n' "$version" "$min_version" | sort -V | tail -n1)" != "$version" ]; then
+            version="$min_version"
+          fi
+
           echo "version=$version" >> "$GITHUB_OUTPUT"
 
       - name: Build native gem with rb-sys-dock