Use rubygems released version of omniauth-cas gem (#28719)

Gemfile.lock

@@ -7,16 +7,6 @@ GIT
       hkdf (~> 0.2)
       jwt (~> 2.0)
 
-GIT
-  remote: https://github.com/dlindahl/omniauth-cas.git
-  revision: 9d9d3a91b316c55d49ab6e621977f2067010c5bf
-  ref: 9d9d3a91b316c55d49ab6e621977f2067010c5bf
-  specs:
-    omniauth-cas (3.0.0)
-      addressable (~> 2.8)
-      nokogiri (~> 1.12)
-      omniauth (~> 2.1)
-
 GIT
   remote: https://github.com/jhawthorn/nsa.git
   revision: e020fcc3a54d993ab45b7194d89ab720296c111b
@@ -484,6 +474,10 @@ GEM
       hashie (>= 3.4.6)
       rack (>= 2.2.3)
       rack-protection
+    omniauth-cas (3.0.0.beta.1)
+      addressable (~> 2.8)
+      nokogiri (~> 1.12)
+      omniauth (~> 2.1)
     omniauth-rails_csrf_protection (1.0.1)
       actionpack (>= 4.2)
       omniauth (~> 2.0)
@@ -894,7 +888,7 @@ DEPENDENCIES
   nsa!
   oj (~> 3.14)
   omniauth (~> 2.0)
-  omniauth-cas!
+  omniauth-cas (~> 3.0.0.beta.1)
   omniauth-rails_csrf_protection (~> 1.0)
   omniauth-saml (~> 2.0)
   omniauth_openid_connect (~> 0.6.1)