Merge pull request #217 from mruby/dependabot/bundler/git-1.19.1

Bump git from 1.13.0 to 1.19.1

Author: matz

Gemfile.lock

@@ -42,7 +42,7 @@ GEM
     ffi (1.15.5)
     forwardable-extended (2.6.0)
     gemoji (4.1.0)
-    git (1.13.0)
+    git (1.19.1)
       addressable (~> 2.8)
       rchardet (~> 1.8)
     github-pages (231)