Upgrade escape_utils to 1.2.1

This matches the version shipped in gitaly-ruby.

The main changes between 1.1.1 and 1.2.1 are CI-related
improvements:
https://github.com/brianmario/escape_utils/compare/1.1.1...1.2.1

Gemfile.lock

@@ -182,7 +182,7 @@ GEM
     encryptor (3.0.0)
     equalizer (0.0.11)
     erubis (2.7.0)
-    escape_utils (1.1.1)
+    escape_utils (1.2.1)
     et-orbi (1.0.3)
       tzinfo
     eventmachine (1.2.7)

Gemfile.rails4.lock

@@ -181,7 +181,7 @@ GEM
     encryptor (3.0.0)
     equalizer (0.0.11)
     erubis (2.7.0)
-    escape_utils (1.1.1)
+    escape_utils (1.2.1)
     et-orbi (1.0.3)
       tzinfo
     eventmachine (1.2.7)