Merge pull request #1422 from gocd/dependabot/bundler/async-2.21.3

Bump async from 2.21.1 to 2.21.3

Gemfile.lock

@@ -17,10 +17,12 @@ GEM
     addressable (2.8.7)
       public_suffix (>= 2.0.2, < 7.0)
     afm (0.2.2)
-    async (2.21.1)
+    async (2.21.3)
       console (~> 1.29)
       fiber-annotation
-      io-event (~> 1.6, >= 1.6.5)
+      io-event (~> 1.7)
+      metrics (~> 0.12)
+      traces (~> 0.15)
     autoprefixer-rails (10.4.19.0)
       execjs (~> 2)
     aws-eventstream (1.3.0)
@@ -107,6 +109,7 @@ GEM
       rb-inotify (~> 0.9, >= 0.9.10)
     logger (1.6.5)
     memoist (0.16.2)
+    metrics (0.12.1)
     middleman (4.5.1)
       coffee-script (~> 2.2)
       haml (>= 4.0.5)
@@ -218,6 +221,7 @@ GEM
     tilt (2.0.11)
     toml (0.3.0)
       parslet (>= 1.8.0, < 3.0.0)
+    traces (0.15.0)
     ttfunk (1.8.0)
       bigdecimal (~> 3.1)
     typhoeus (1.4.1)