liquibase: update livecheck

The existing `livecheck` block for `liquibase` is returning an
`Unable to get versions` error, as the URL now redirects to
https://www.liquibase.com/download-pro and that page links to a Pro
tarball instead of the OSS distribution that the formula uses. The OSS
download page can be found at https://www.liquibase.com/download-oss
but the tarball link is hosted on package.liquibase.com, not GitHub.

This resolves the issue by updating the `livecheck` block to simply
use the `GithubLatest` strategy, as the formula is using a GitHub
release asset.

Author: samford

Formula/l/liquibase.rb

@@ -6,8 +6,8 @@ class Liquibase < Formula
   license "Apache-2.0"
 
   livecheck do
-    url "https://www.liquibase.com/download"
-    regex(/href=.*?liquibase[._-]v?(\d+(?:\.\d+)+)\.t/i)
+    url :stable
+    strategy :github_latest
   end
 
   no_autobump! because: :requires_manual_review