Important Fix for 0.21

Release 0.21 had a major flaw. First, during a refactoring we lost the test coverage for compilation failures. Then, during a refactoring we accidentally dropped the diagnostic gathering, so TypeScript files were not actually type-checked.

This release also fixes a warning about deprecated Buffer constructor

BREAKING CHANGES:

• rules_typescript_dependencies() will no longer install transitive dependencies of build_bazel_rules_nodejs. User WORKSPACE files will now need to install rules_nodejs transitive deps directly:

  load("@build_bazel_rules_nodejs//:package.bzl", "rules_nodejs_dependencies")
  rules_nodejs_dependencies()