Bump loofah from 2.2.3 to 2.3.1 (#858)

Bumps [loofah](https://github.com/flavorjones/loofah) from 2.2.3 to 2.3.1.
- [Release notes](https://github.com/flavorjones/loofah/releases)
- [Changelog](https://github.com/flavorjones/loofah/blob/master/CHANGELOG.md)
- [Commits](https://github.com/flavorjones/loofah/compare/v2.2.3...v2.3.1)

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

Gemfile.lock

@@ -112,7 +112,7 @@ GEM
       tins (~> 1.6)
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
-    crass (1.0.4)
+    crass (1.0.5)
     diff-lcs (1.3)
     docile (1.3.2)
     dotenv (2.7.4)
@@ -162,7 +162,7 @@ GEM
       activesupport (>= 4)
       railties (>= 4)
       request_store (~> 1.0)
-    loofah (2.2.3)
+    loofah (2.3.1)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -182,7 +182,7 @@ GEM
     multipart-post (2.1.1)
     net-ldap (0.16.1)
     nio4r (2.4.0)
-    nokogiri (1.10.4)
+    nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     oauth (0.5.4)
     oauth2 (1.4.1)