v0.6.3

What's Changed

• Add metadata for rubygems.org by @m-nakamura145 in #358
• Add badges in README by @ydah in #360
• Organize gemspec by @ydah in #359
• Add a Table of Contents in README by @ydah in #361
• Adding an overview of Parameterizing rules to the README by @ydah in #363
• Add test or steep check by rake task in README by @ydah in #362
• Use def_delegators in Lrama::States::Item by @ydah in #365
• chore: trivial refactoring by @ydah in #366
• Refactoring to extract Lrama::Grammar::Symbols by @ydah in #364
• Add rbs for Grammar::Type and Grammar::Symbols::Resolver by @ydah in #368
• Separate number and index in Grammar::Reference by @ydah in #370
• Provide functionalities for Bring Your Own Stack by @yui-knk in #367
• #scan_reference should fill Reference#number for $:n. by @yui-knk in #371
• v0.6.3 by @yui-knk in #372

Full Changelog: v0.6.2...v0.6.3