update minitest gem

Author: dgodd

Gemfile.lock

@@ -9,7 +9,7 @@ GEM
     httparty (0.14.0)
       multi_xml (>= 0.5.2)
     json (2.3.0)
-    minitest (5.10.1)
+    minitest (5.14.1)
     multi_xml (0.6.0)
     public_suffix (4.0.5)
     rake (13.0.1)