Update oauth2 to 1.4.4 fixing faraday constraint

Fixes an unsatisfiable constraint in the Gemfile.lock at the moment,
where oauth2 wants < 0.16.0 but we are already at 0.17.3

Gemfile.lock

@@ -662,8 +662,8 @@ GEM
       shellany (~> 0.0)
     numerizer (0.2.0)
     oauth (0.5.4)
-    oauth2 (1.4.1)
-      faraday (>= 0.8, < 0.16.0)
+    oauth2 (1.4.4)
+      faraday (>= 0.8, < 2.0)
       jwt (>= 1.0, < 3.0)
       multi_json (~> 1.3)
       multi_xml (~> 0.5)