Bump rdoc from 6.5.0 to 6.6.0 (#202)

Bumps [rdoc](https://github.com/ruby/rdoc) from 6.5.0 to 6.6.0.
- [Release notes](https://github.com/ruby/rdoc/releases)
- [Changelog](https://github.com/ruby/rdoc/blob/master/History.rdoc)
- [Commits](https://github.com/ruby/rdoc/compare/v6.5.0...v6.6.0)

---
updated-dependencies:
- dependency-name: rdoc
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile

@@ -6,4 +6,4 @@ gem "rugged", "~> 1.5.1"
 gem "liquid", "~> 5.4"
 
 gem "irb", "~> 1.9", :group => [:development]
-gem "rdoc", "~> 6.4", :group => [:development]
+gem "rdoc", "~> 6.6", :group => [:development]

Gemfile.lock

@@ -8,7 +8,7 @@ GEM
     liquid (5.4.0)
     psych (5.1.1.1)
       stringio
-    rdoc (6.5.0)
+    rdoc (6.6.0)
       psych (>= 4.0.0)
     reline (0.4.1)
       io-console (~> 0.5)
@@ -21,7 +21,7 @@ PLATFORMS
 DEPENDENCIES
   irb (~> 1.9)
   liquid (~> 5.4)
-  rdoc (~> 6.4)
+  rdoc (~> 6.6)
   rugged (~> 1.5.1)
 
 BUNDLED WITH