Merge branch 'ruby-parser-rb-2-6' into 'master'

Update ruby_parser for ruby 2.6

See merge request gitlab-org/gitlab-ce!28295

Gemfile.lock

@@ -812,7 +812,7 @@ GEM
     ruby-progressbar (1.10.0)
     ruby-saml (1.7.2)
       nokogiri (>= 1.5.10)
-    ruby_parser (3.11.0)
+    ruby_parser (3.13.1)
       sexp_processor (~> 4.9)
     rubyntlm (0.6.2)
     rubypants (0.2.0)
@@ -852,7 +852,7 @@ GEM
     sentry-raven (2.9.0)
       faraday (>= 0.7.6, < 1.0)
     settingslogic (2.0.9)
-    sexp_processor (4.11.0)
+    sexp_processor (4.12.0)
     sham_rack (1.3.6)
       rack
     shoulda-matchers (3.1.2)