Bump doorkeeper from 5.6.5 to 5.6.6 (#24399)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -221,7 +221,7 @@ GEM
     docile (1.4.0)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
-    doorkeeper (5.6.5)
+    doorkeeper (5.6.6)
       railties (>= 5)
     dotenv (2.8.1)
     dotenv-rails (2.8.1)
@@ -396,7 +396,7 @@ GEM
       activesupport (>= 4)
       railties (>= 4)
       request_store (~> 1.0)
-    loofah (2.19.1)
+    loofah (2.20.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.8.1)