Bump mini_magick

Gemfile

@@ -79,7 +79,7 @@ gem "activerecord-import", "0.27.0"
 
 gem "carrierwave", "1.2.3"
 gem "fog-aws",     "3.3.0"
-gem "mini_magick", "4.8.0"
+gem "mini_magick", "4.9.2"
 
 # GUID generation
 gem "uuid", "2.3.8"

Gemfile.lock

@@ -382,7 +382,7 @@ GEM
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
-    mini_magick (4.8.0)
+    mini_magick (4.9.2)
     mini_mime (1.0.1)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
@@ -817,7 +817,7 @@ DEPENDENCIES
   logging-rails (= 0.6.0)
   markdown-it-html5-embed (= 1.0.0)
   markerb (= 1.1.0)
-  mini_magick (= 4.8.0)
+  mini_magick (= 4.9.2)
   minitest
   mobile-fu (= 1.4.0)
   mysql2 (= 0.5.2)