Merge pull request #3443 from mlibrary/dependabot/bundler/rack-2.2.6.3

Bump rack from 2.2.6.2 to 2.2.6.3

Author: conorom

Gemfile.lock

@@ -741,7 +741,7 @@ GEM
       rails (>= 5.0, < 6.2)
       rdf
     racc (1.6.1)
-    rack (2.2.6.2)
+    rack (2.2.6.3)
     rack-protection (2.2.3)
       rack
     rack-proxy (0.7.0)