ML Metadata v1.2.0

Major Features and Improvements

• Open sources declarative nodes filtering with zetaSQL. It is currently
  supported on Linux and MacOS 10.14+.
• Extends get_artifacts, get_executions, get_contexts APIs with filtering
  capabilities on properties and 1-hop neighborhood nodes.
• Supports configure GRPC options grpc.http2.max_ping_strikes from the
  python client.

Bug Fixes and Other Changes

• Introduces database_name_ field for MySQL MetadataSource implementation to
  enable MySQLMetadataSource to switch to different databases within the same
  SQL server after connection or during reconnection.

Breaking Changes

• The minimum required OS version for the macOS is 10.14 now.
• Bumped the minimum bazel version required to build ml_metadata to 3.7.2.

Deprecations

• N/A