Bump rubocop

Use old style for Style/PercentLiteralDelimiters for now. Maybe we can
change this in the future, because the ruby style guide suggests to use
`[]` (which is also the new default for rubocop).

closes #7443#

.rubocop.yml

@@ -164,6 +164,16 @@ Lint/Debugger:
 Style/NumericPredicate:
   EnforcedStyle: comparison
 
+# Old defaults from rubocop < 0.48.1
+Style/PercentLiteralDelimiters:
+  PreferredDelimiters:
+    default: '()'
+    '%i': '()'
+    '%I': '()'
+    '%r': '{}'
+    '%w': '()'
+    '%W': '()'
+
 # Reset some HoundCI changes back to Rubocop defaults
 Style/DotPosition:
   EnforcedStyle: leading

Gemfile

@@ -252,7 +252,7 @@ group :development do
   gem "pronto-haml",    "0.9.0", require: false
   gem "pronto-rubocop", "0.9.0", require: false
   gem "pronto-scss",    "0.9.1", require: false
-  gem "rubocop",        "0.47.1"
+  gem "rubocop",        "0.48.1", require: false
 
   # Preloading environment
 

Gemfile.lock

@@ -595,7 +595,7 @@ GEM
       rspec-mocks (~> 3.5.0)
       rspec-support (~> 3.5.0)
     rspec-support (3.5.0)
-    rubocop (0.47.1)
+    rubocop (0.48.1)
       parser (>= 2.3.3.1, < 3.0)
       powerpack (~> 0.1)
       rainbow (>= 1.99.1, < 3.0)
@@ -862,7 +862,7 @@ DEPENDENCIES
   redcarpet (= 3.4.0)
   responders (= 2.3.0)
   rspec-rails (= 3.5.2)
-  rubocop (= 0.47.1)
+  rubocop (= 0.48.1)
   ruby-oembed (= 0.10.1)
   rubyzip (= 1.2.1)
   sass-rails (= 5.0.6)