Version 0.7.0

Refactoring work by @lebensterben

• Major changes in lychee-lib::filter module:
  • Fields in Excludes except the RegexSet is now moved to Filter.
  • Filter contains Option<Excludes> and Option<Includes>, which are
    wrapper struct of RegexSet instead of Option<RegexSet>. As a result
    the code now looks cleaner.
  • Factored out some filtering logics to dedicated functions.
    • It's possible to write tests for those functions in addition to tests
      for the Filter struct.
  • Added docs to Filter::is_excluded and reorgnized the code.
• placed derive_builder by typed_builder:
  • The internal interface very ugly, as admitted by the author, but we no
    longer have nested Options like before.
  • As a result, the Client building is much easier to read.
  • Main benefit of typed_builder is, the arguments feeded to builder is
    checked at compile time instead of run-time.
• Fixed a bug in lychee::tests::usage and lychee-lib::stats::test.
  • Now it will clear environment variable which would otherwise cause an
    issue if GITHUB_TOKEN is set.
• Updated dependencies.