[Security] Bump omniauth from 1.9.0 to 1.9.1

Bumps [omniauth](https://github.com/omniauth/omniauth) from 1.9.0 to 1.9.1. **This update includes a security fix.**
- [Release notes](https://github.com/omniauth/omniauth/releases)
- [Commits](omniauth/omniauth@v1.9.0...v1.9.1)

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

Gemfile.lock

@@ -148,7 +148,7 @@ GEM
       sprockets (>= 2.0.0)
       tilt (>= 1.2)
     hashdiff (1.0.0)
-    hashie (3.6.0)
+    hashie (4.1.0)
     i18n (1.8.2)
       concurrent-ruby (~> 1.0)
     icalendar (2.6.1)
@@ -211,8 +211,8 @@ GEM
       multi_xml (~> 0.5)
       rack (>= 1.2, < 3)
     oj (3.10.2)
-    omniauth (1.9.0)
-      hashie (>= 3.4.6, < 3.7.0)
+    omniauth (1.9.1)
+      hashie (>= 3.4.6)
       rack (>= 1.6.2, < 3)
     omniauth-facebook (6.0.0)
       omniauth-oauth2 (~> 1.2)