feat(artifact_proxy): add Dart SDK patterns to manifest (#2295)

packages/artifact_proxy/tool/generate_manifest.sh

@@ -48,6 +48,12 @@ artifact_overrides:
   - flutter_infra_release/flutter/\$engine/android-x64-release/symbols.zip
   - flutter_infra_release/flutter/\$engine/android-x64-release/windows-x64.zip
 
+  # Dart SDK
+  - flutter_infra_release/flutter/\$engine/dart-sdk-darwin-arm64.zip
+  - flutter_infra_release/flutter/\$engine/dart-sdk-darwin-x64.zip
+  - flutter_infra_release/flutter/\$engine/dart-sdk-linux-x64.zip
+  - flutter_infra_release/flutter/\$engine/dart-sdk-windows-x64.zip
+
   # embedding release
   - download.flutter.io/io/flutter/flutter_embedding_release/1.0.0-\$engine/flutter_embedding_release-1.0.0-\$engine.pom
   - download.flutter.io/io/flutter/flutter_embedding_release/1.0.0-\$engine/flutter_embedding_release-1.0.0-\$engine.jar