ocenaudio: update livecheck

The existing `livecheck` block for `ocenaudio` checks the upstream
changelog page and parses the version links in the HTML. This works
but each of the cask `url`s return a 200 response that has a
`Content-Disposition` header with a versioned filename, so it makes
more sense to check that instead. These files use the same version at
the moment but using `HeaderMatch` to identify the version from the
`url` response ensures that we're checking each upstream file version
instead of assuming that they will always be the same.

Casks/o/ocenaudio.rb

@@ -22,8 +22,8 @@
   homepage "https://www.ocenaudio.com/en"
 
   livecheck do
-    url "https://www.ocenaudio.com/changelog"
-    regex(/download\?version=v?(\d+(?:\.\d+)+)/i)
+    url :url
+    strategy :header_match
   end
 
   depends_on macos: ">= :sierra"