CCA: Remove the usage of "master" branch in README

Bug: 1123783
Test: CQ
Change-Id: I89fdcae6b7be07326137f2c7cc03c77ac49e7646
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2505360
Auto-Submit: Shik Chen <shik@chromium.org>
Reviewed-by: Wei Lee <wtlee@chromium.org>
Commit-Queue: Wei Lee <wtlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822008}

chromeos/components/camera_app_ui/resources/js/lib/README.md

 # analytics.js
 
 * [Project Page](https://developers.google.com/analytics/devguides/collection/analyticsjs)
-* The extern file [universal_analytics_api.js]((https://github.com/google/closure-compiler/blob/master/contrib/externs/universal_analytics_api.js)) is copied from the [closure compiler project](https://github.com/google/closure-compiler)
+* The extern file [universal_analytics_api.js](https://github.com/google/closure-compiler/blob/4327b35e038666593b0c72f90e75c4f33fc7a060/contrib/externs/universal_analytics_api.js) is copied from the [closure compiler project](https://github.com/google/closure-compiler)
 
 # comlink.js