Bump parser from 2.6.2.1 to 2.6.3.0

Bumps [parser](https://github.com/whitequark/parser) from 2.6.2.1 to 2.6.3.0.
- [Release notes](https://github.com/whitequark/parser/releases)
- [Changelog](https://github.com/whitequark/parser/blob/master/CHANGELOG.md)
- [Commits](whitequark/parser@v2.6.2.1...v2.6.3.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

Gemfile.lock

@@ -6,7 +6,7 @@ GEM
     jaro_winkler (1.5.2)
     minitest (5.11.3)
     parallel (1.17.0)
-    parser (2.6.2.1)
+    parser (2.6.3.0)
       ast (~> 2.4.0)
     psych (3.1.0)
     rainbow (3.0.0)