Update parser gem to 3.0.2.0

This removes the warnings relating to Ruby 2.7.4.

Diff: https://my.diffend.io/gems/parser/3.0.0.0/3.0.2.0

Changelog: changed

Gemfile.lock

@@ -900,7 +900,7 @@ GEM
     orm_adapter (0.5.0)
     os (1.1.1)
     parallel (1.20.1)
-    parser (3.0.0.0)
+    parser (3.0.2.0)
       ast (~> 2.4.1)
     parslet (1.8.2)
     pastel (0.8.0)