chore(deps): bump rdoc from 3.12.1 to 6.3.1

Bumps [rdoc](https://github.com/ruby/rdoc) from 3.12.1 to 6.3.1.
- [Release notes](https://github.com/ruby/rdoc/releases)
- [Changelog](https://github.com/ruby/rdoc/blob/master/History.rdoc)
- [Commits](ruby/rdoc@v3.12.1...v6.3.1)

---
updated-dependencies:
- dependency-name: rdoc
  dependency-type: direct:production
...

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

Gemfile

@@ -4,7 +4,7 @@ gem "licensee", ">= 9.9.0"
 gem "github-linguist", ">= 7.12.1"
 gem "commonmarker", "~> 0.23.4"
 gem "RedCloth", "~> 4.3"
-gem "rdoc", "3.12.1"
+gem "rdoc", "6.3.1"
 gem "org-ruby", "~> 0.9.12"
 gem "creole", "~> 0.5.0"
 gem "wikicloth", "~> 0.8.3"

Gemfile.lock

@@ -25,7 +25,6 @@ GEM
     github-markup (4.0.0)
     htmlentities (4.3.4)
     idn-ruby (0.1.0)
-    json (1.8.6)
     licensee (9.15.1)
       dotenv (~> 2.0)
       octokit (~> 4.20)
@@ -45,8 +44,7 @@ GEM
       rubypants (~> 0.2)
     public_suffix (4.0.6)
     racc (1.6.0)
-    rdoc (3.12.1)
-      json (~> 1.4)
+    rdoc (6.3.1)
     reverse_markdown (1.4.0)
       nokogiri
     ruby2_keywords (0.0.4)
@@ -81,7 +79,7 @@ DEPENDENCIES
   github-markup (~> 4.0)
   licensee (>= 9.9.0)
   org-ruby (~> 0.9.12)
-  rdoc (= 3.12.1)
+  rdoc (= 6.3.1)
   wikicloth (~> 0.8.3)
 
 BUNDLED WITH