Update rubocop to version 0.81.0

Author: depfu[bot]

Gemfile.lock

@@ -121,7 +121,7 @@ GEM
     nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
     parallel (1.19.1)
-    parser (2.7.0.3)
+    parser (2.7.0.5)
       ast (~> 2.4.0)
     pg (0.21.0)
     pry (0.12.2)
@@ -164,14 +164,14 @@ GEM
     rb-readline (0.5.5)
     regexp_parser (1.6.0)
     rexml (3.2.4)
-    rubocop (0.80.1)
+    rubocop (0.81.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
       parser (>= 2.7.0.1)
       rainbow (>= 2.2.2, < 4.0)
       rexml
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 1.7)
+      unicode-display_width (>= 1.4.0, < 2.0)
     ruby-progressbar (1.10.1)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
@@ -208,7 +208,7 @@ GEM
       thread_safe (~> 0.1)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
-    unicode-display_width (1.6.1)
+    unicode-display_width (1.7.0)
     web-console (3.7.0)
       actionview (>= 5.0)
       activemodel (>= 5.0)