[Security] Bump loofah from 2.3.0 to 2.3.1

Bumps [loofah](https://github.com/flavorjones/loofah) from 2.3.0 to 2.3.1. **This update includes a security fix.**
- [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/v2.3.0...v2.3.1)

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

Gemfile.lock

@@ -156,7 +156,7 @@ GEM
       term-ansicolor (~> 1.3)
       thor (~> 0.19.4)
       tins (~> 1.6)
-    crass (1.0.4)
+    crass (1.0.5)
     daemons (1.2.6)
     dalli (2.7.6)
     database_cleaner (1.7.0)
@@ -316,7 +316,7 @@ GEM
       actionmailer (>= 3.2)
       letter_opener (~> 1.0)
       railties (>= 3.2)
-    loofah (2.3.0)
+    loofah (2.3.1)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)