Bump omniauth from 1.8.1 to 2.1.1 in /backend

Bumps [omniauth](https://github.com/omniauth/omniauth) from 1.8.1 to 2.1.1.
- [Release notes](https://github.com/omniauth/omniauth/releases)
- [Commits](omniauth/omniauth@v1.8.1...v2.1.1)

---
updated-dependencies:
- dependency-name: omniauth
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

backend/Gemfile

@@ -24,7 +24,7 @@ gem "cancancan", "~> 3.3.0"
 gem "cancancan-mongoid", "2.0.0"
 gem "devise", "4.8.0"
 gem "devise_invitable", "2.0.5"
-gem "omniauth", "1.8.1"
+gem "omniauth", "2.1.1"
 gem "omniauth-facebook", "3.0.0"
 
 # Colored output to console

backend/Gemfile.lock

@@ -183,7 +183,7 @@ GEM
       activerecord (>= 4.2, < 7.0)
       request_store (~> 1.0)
     hashdiff (1.0.1)
-    hashie (3.5.7)
+    hashie (5.0.0)
     httpclient (2.8.3)
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
@@ -267,14 +267,15 @@ GEM
       multi_json (~> 1.3)
       multi_xml (~> 0.5)
       rack (>= 1.2, < 3)
-    omniauth (1.8.1)
-      hashie (>= 3.4.6, < 3.6.0)
-      rack (>= 1.6.2, < 3)
+    omniauth (2.1.1)
+      hashie (>= 3.4.6)
+      rack (>= 2.2.3)
+      rack-protection
     omniauth-facebook (3.0.0)
       omniauth-oauth2 (~> 1.2)
-    omniauth-oauth2 (1.5.0)
-      oauth2 (~> 1.1)
-      omniauth (~> 1.2)
+    omniauth-oauth2 (1.8.0)
+      oauth2 (>= 1.4, < 3)
+      omniauth (~> 2.0)
     orm_adapter (0.5.0)
     parallel (1.23.0)
     parser (3.2.2.3)
@@ -313,6 +314,8 @@ GEM
     rack (2.2.8)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
+    rack-protection (3.1.0)
+      rack (~> 2.2, >= 2.2.4)
     rack-test (2.1.0)
       rack (>= 1.3)
     rack-timeout (0.6.0)
@@ -498,7 +501,7 @@ DEPENDENCIES
   mongoid (= 7.3.3)
   mongoid-rspec
   nearest_time_zone
-  omniauth (= 1.8.1)
+  omniauth (= 2.1.1)
   omniauth-facebook (= 3.0.0)
   pg (= 1.2.3)
   pry-byebug