Relax dependency on rdoc (ruby 2.5 comes with rdoc 6.0)

debian/patches/0488-relax-rdoc.patch

@@ -0,0 +1,11 @@
+--- a/Gemfile
++++ b/Gemfile
+@@ -137,7 +137,7 @@
+ gem 'github-markup', '~> 1.7.0', require: 'github/markup'
+ gem 'commonmarker', '~> 0.20'
+ gem 'RedCloth', '~> 4.3.2'
+-gem 'rdoc', '~> 6.1'
++gem 'rdoc', '~> 6.0'
+ gem 'org-ruby', '~> 0.9.12'
+ gem 'creole', '~> 0.5.0'
+ gem 'wikicloth', '0.8.1'

debian/patches/series

@@ -16,6 +16,7 @@
 0485-relax-responders.patch
 0486-relax-grpc-protobuf.patch
 0487-relax-rack-cors.patch
+0488-relax-rdoc.patch
 0500-set-webpack-root.patch
 0510-remove-dev-dependencies.patch
 0520-add-system-lib-path-for-webpack.patch