nvchecker: add some more Ruby packages

* ruby-mdl
* ruby-kramdown-parser-gfm
* ruby-tomlrb
* ruby-mixlib-shellout
* ruby-mixlib-cli
* ruby-mixlib-config
* ruby-chef-utils

.repo/nvchecker.toml

@@ -710,6 +710,34 @@ use_max_tag = true
 
 # gems
 
+[ruby-mdl]
+source = "gems"
+gems = "mdl"
+
+[ruby-kramdown-parser-gfm]
+source = "gems"
+gems = "kramdown-parser-gfm"
+
+[ruby-tomlrb]
+source = "gems"
+gems = "tomlrb"
+
+[ruby-mixlib-shellout]
+source = "gems"
+gems = "mixlib-shellout"
+
+[ruby-mixlib-cli]
+source = "gems"
+gems = "mixlib-cli"
+
+[ruby-mixlib-config]
+source = "gems"
+gems = "mixlib-config"
+
+[ruby-chef-utils]
+source = "gems"
+gems = "chef-utils"
+
 [ruby-opener]
 source = "gems"
 gems = "opener"