Bump rubocop from 0.60.0 to 0.61.1 (#515)

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.60.0 to 0.61.1.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.60.0...v0.61.1)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Gemfile

@@ -10,6 +10,6 @@ gem "minitest", "~> 5.11"
 gem "pry", "0.12.2"
 gem "rake", "~> 12.3"
 gem "rake-compiler", "~> 1.0"
-gem "rubocop", "0.60.0"
+gem "rubocop", "0.61.1"
 gem "simplecov", "0.16.1"
 gem "yard", "0.9.16"

Gemfile.lock

@@ -44,7 +44,7 @@ GEM
     rake (12.3.1)
     rake-compiler (1.0.5)
       rake
-    rubocop (0.60.0)
+    rubocop (0.61.1)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
       parser (>= 2.5, != 2.5.1.1)
@@ -77,7 +77,7 @@ DEPENDENCIES
   pry (= 0.12.2)
   rake (~> 12.3)
   rake-compiler (~> 1.0)
-  rubocop (= 0.60.0)
+  rubocop (= 0.61.1)
   simplecov (= 0.16.1)
   yard (= 0.9.16)