Bump rubocop from 0.49.1 to 0.50.0

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.49.1 to 0.50.0.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.49.1...v0.50.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

Gemfile.lock

@@ -63,9 +63,9 @@ GEM
     nap (1.1.0)
     netrc (0.11.0)
     parallel (1.12.1)
-    parser (2.4.0.2)
-      ast (~> 2.3)
-    powerpack (0.1.1)
+    parser (2.5.1.2)
+      ast (~> 2.4.0)
+    powerpack (0.1.2)
     rainbow (2.2.2)
       rake
     rake (12.3.0)
@@ -82,19 +82,19 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.7.0)
     rspec-support (3.7.1)
-    rubocop (0.49.1)
+    rubocop (0.50.0)
       parallel (~> 1.10)
       parser (>= 2.3.3.1, < 3.0)
       powerpack (~> 0.1)
-      rainbow (>= 1.99.1, < 3.0)
+      rainbow (>= 2.2.2, < 3.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 1.0, >= 1.0.1)
     ruby-macho (1.3.1)
-    ruby-progressbar (1.9.0)
+    ruby-progressbar (1.10.0)
     thread_safe (0.3.6)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    unicode-display_width (1.3.0)
+    unicode-display_width (1.4.0)
     xcodeproj (1.6.0)
       CFPropertyList (>= 2.3.3, < 4.0)
       atomos (~> 0.1.3)