redisinsight: update livecheck

The existing `livecheck` block for `redisinsight` checks the Git tags
from the related GitHub repository, as the first-party website
doesn't publish version information. livecheck already uses the `Git`
strategy for the GitHub URL by default, so this `#strategy` call
isn't necessary.

This resolves the redundancy by updating the call to use the
`GithubLatest` strategy instead, as that is more likely to align with
releases on the first-party website. Besides that, it should also omit
unstable versions like `2.0.2-preview`, `2.0.2-preview-rc1`, etc.
that the existing approach is matching (without a strict regex).

Casks/r/redisinsight.rb

@@ -15,7 +15,7 @@
   # GitHub releases as a best guess of when a new version is released.
   livecheck do
     url "https://github.com/RedisInsight/RedisInsight"
-    strategy :git
+    strategy :github_latest
   end
 
   auto_updates true