Upgrade ActionCable npm package

This is to match our Rails version 6.0.3. No actual changes were made
to ActionCable in this patch release

package.json

@@ -43,7 +43,7 @@
     "@gitlab/svgs": "1.127.0",
     "@gitlab/ui": "14.10.0",
     "@gitlab/visual-review-tools": "1.6.1",
-    "@rails/actioncable": "^6.0.2-2",
+    "@rails/actioncable": "^6.0.3",
     "@sentry/browser": "^5.10.2",
     "@sourcegraph/code-host-integration": "0.0.46",
     "@toast-ui/editor": "^2.0.1",

yarn.lock

@@ -983,10 +983,10 @@
     consola "^2.10.1"
     node-fetch "^2.6.0"
 
-"@rails/actioncable@^6.0.2-2":
-  version "6.0.2-2"
-  resolved "https://registry.yarnpkg.com/@rails/actioncable/-/actioncable-6.0.2-2.tgz#237907f8111707950381387c273b19ac25958408"
-  integrity sha512-0sKStf8hnberH1TKup10PJ92JT2dVqf3gf+OT4lJ7DiYSBEuDcvICHxWsyML2oWTpjUhC4kLvUJ3pXL2JJrJuQ==
+"@rails/actioncable@^6.0.3":
+  version "6.0.3"
+  resolved "https://registry.yarnpkg.com/@rails/actioncable/-/actioncable-6.0.3.tgz#722b4b639936129307ddbab3a390f6bcacf3e7bc"
+  integrity sha512-I01hgqxxnOgOtJTGlq0ZsGJYiTEEiSGVEGQn3vimZSqEP1HqzyFNbzGTq14Xdyeow2yGJjygjoFF1pmtE+SQaw==
 
 "@sentry/browser@^5.10.2":
   version "5.10.2"