Bump rubocop-govuk from 3.17.0 to 3.17.1

Bumps [rubocop-govuk](https://github.com/alphagov/rubocop-govuk) from 3.17.0 to 3.17.1.
- [Release notes](https://github.com/alphagov/rubocop-govuk/releases)
- [Changelog](https://github.com/alphagov/rubocop-govuk/blob/master/CHANGELOG.md)
- [Commits](alphagov/rubocop-govuk@v3.17.0...v3.17.1)

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

Gemfile.lock

@@ -191,7 +191,7 @@ GEM
       mini_portile2 (~> 2.4.0)
     null_logger (0.0.1)
     parallel (1.19.2)
-    parser (2.7.1.4)
+    parser (2.7.2.0)
       ast (~> 2.4.1)
     phantomjs (2.1.1.0)
     plek (4.0.0)
@@ -247,7 +247,7 @@ GEM
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    regexp_parser (1.8.0)
+    regexp_parser (1.8.2)
     request_store (1.5.0)
       rack (>= 1.4)
     rest-client (2.1.0)
@@ -267,17 +267,18 @@ GEM
       rubocop-ast (>= 0.1.0, < 1.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 2.0)
-    rubocop-ast (0.3.0)
-      parser (>= 2.7.1.4)
-    rubocop-govuk (3.17.0)
+    rubocop-ast (0.8.0)
+      parser (>= 2.7.1.5)
+    rubocop-govuk (3.17.1)
       rubocop (= 0.87.1)
-      rubocop-rails (= 2.6.0)
+      rubocop-ast (= 0.8.0)
+      rubocop-rails (= 2.8.1)
       rubocop-rake (= 0.5.1)
       rubocop-rspec (= 1.42.0)
-    rubocop-rails (2.6.0)
+    rubocop-rails (2.8.1)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
-      rubocop (>= 0.82.0)
+      rubocop (>= 0.87.0)
     rubocop-rake (0.5.1)
       rubocop
     rubocop-rspec (1.42.0)