Bump omniauth-oauth version to v1.2.0

This relaxes the OmniAuth version to enable us to upgrade to v2.
No code changes were made:
https://my.diffend.io/gems/omniauth-oauth/1.1.0/1.2.0

This gem is only used by the Twitter OAuth at the moment.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/30073

Changelog: changed

Gemfile.lock

@@ -896,9 +896,9 @@ GEM
       jwt (>= 2.0)
       omniauth (>= 1.1.1)
       omniauth-oauth2 (>= 1.5)
-    omniauth-oauth (1.1.0)
+    omniauth-oauth (1.2.0)
       oauth
-      omniauth (~> 1.0)
+      omniauth (>= 1.0, < 3)
     omniauth-oauth2 (1.7.3)
       oauth2 (>= 1.4, < 3)
       omniauth (>= 1.9, < 3)