Bump loofah from 2.3.0 to 2.3.1 in /spec/integration/rails_4.2.0 (#681)

Bumps [loofah](https://github.com/flavorjones/loofah) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/flavorjones/loofah/releases)
- [Changelog](https://github.com/flavorjones/loofah/blob/master/CHANGELOG.md)
- [Commits](flavorjones/loofah@v2.3.0...v2.3.1)

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

spec/integration/rails_4.2.0/Gemfile.lock

@@ -53,7 +53,7 @@ GEM
       execjs
     coffee-script-source (1.9.1)
     concurrent-ruby (1.1.5)
-    crass (1.0.4)
+    crass (1.0.5)
     erubis (2.7.0)
     execjs (2.4.0)
     globalid (0.3.3)
@@ -69,7 +69,7 @@ GEM
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     json (1.8.6)
-    loofah (2.3.0)
+    loofah (2.3.1)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.6.3)
@@ -78,7 +78,7 @@ GEM
     mini_portile2 (2.4.0)
     minitest (5.12.2)
     multi_json (1.11.0)
-    nokogiri (1.10.4)
+    nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     rack (1.6.11)
     rack-test (0.6.3)