Merge pull request #716 from coderdojo-japan/dependabot/bundler/mimemagic-0.3.4

Bump mimemagic from 0.3.3 to 0.3.4

Author: yasulab

Gemfile.lock

@@ -197,7 +197,7 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2019.1009)
-    mimemagic (0.3.3)
+    mimemagic (0.3.4)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.0)