[Security] Bump omniauth from 1.7.1 to 1.9.1

Bumps [omniauth](https://github.com/omniauth/omniauth) from 1.7.1 to 1.9.1. **This update includes a security fix.**
- [Release notes](https://github.com/omniauth/omniauth/releases)
- [Commits](omniauth/omniauth@v1.7.1...v1.9.1)

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

Gemfile

@@ -19,7 +19,7 @@ gem 'pg', '~> 0.18.2'
 gem 'activerecord-postgresql-adapter'
 
 gem 'devise', '~> 3.5.5'
-gem 'omniauth', '~> 1.7.1' # 1.2.2 breaks test sign_in
+gem 'omniauth', '~> 1.9.1' # 1.2.2 breaks test sign_in
 gem 'omniauth-shibboleth', '~> 1.2.1'
 gem 'equivalent-xml', '~> 0.6.0'
 

Gemfile.lock

@@ -158,7 +158,7 @@ GEM
     ffi (1.11.1)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
-    hashie (3.5.6)
+    hashie (4.1.0)
     hike (1.2.3)
     honeycomb-beeline (1.0.0)
       libhoney (~> 1.8)
@@ -255,8 +255,8 @@ GEM
       mediashelf-loggable
       nokogiri (>= 1.4.2)
       solrizer (~> 3.1.0)
-    omniauth (1.7.1)
-      hashie (>= 3.4.6, < 3.6.0)
+    omniauth (1.9.1)
+      hashie (>= 3.4.6)
       rack (>= 1.6.2, < 3)
     omniauth-shibboleth (1.2.1)
       omniauth (>= 1.0.0)
@@ -483,7 +483,7 @@ DEPENDENCIES
   logstash-event (= 1.2.02)
   minitest (~> 5.10.2)
   nokogiri (= 1.10.8)
-  omniauth (~> 1.7.1)
+  omniauth (~> 1.9.1)
   omniauth-shibboleth (~> 1.2.1)
   pg (~> 0.18.2)
   poltergeist (= 1.15.0)