v1.6.1

• Store: add option to pass debug flags. #134
• Add // coverage:ignore-file to generated objectbox.g.dart skipping this file from coverage test.
• Increase supported analyzer to v4. #443
• Update documentation on Query streams using watch to highlight it is a single-subscription
  stream that can only be listened to once. Also updated code examples to not imply the stream is
  re-usable.
• Update: objectbox-android 3.2.1.