Update bundler and gems (#23)

Gemfile.lock

@@ -2,27 +2,27 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
-    json (2.6.2)
-    parallel (1.22.1)
-    parser (3.1.2.1)
+    json (2.6.3)
+    parallel (1.23.0)
+    parser (3.2.2.1)
       ast (~> 2.4.1)
     rainbow (3.1.1)
-    regexp_parser (2.6.0)
+    regexp_parser (2.8.0)
     rexml (3.2.5)
-    rubocop (1.37.0)
+    rubocop (1.51.0)
       json (~> 2.3)
       parallel (~> 1.10)
-      parser (>= 3.1.2.1)
+      parser (>= 3.2.0.0)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
       rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.22.0, < 2.0)
+      rubocop-ast (>= 1.28.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 3.0)
-    rubocop-ast (1.22.0)
-      parser (>= 3.1.1.0)
-    ruby-progressbar (1.11.0)
-    unicode-display_width (2.3.0)
+      unicode-display_width (>= 2.4.0, < 3.0)
+    rubocop-ast (1.28.1)
+      parser (>= 3.2.1.0)
+    ruby-progressbar (1.13.0)
+    unicode-display_width (2.4.2)
 
 PLATFORMS
   ruby
@@ -31,4 +31,4 @@ DEPENDENCIES
   rubocop (~> 1.4)
 
 BUNDLED WITH
-   2.2.33
+   2.4.10