feat: support rc version (#72)

action.yml

@@ -18,6 +18,8 @@ outputs:
     description: "The Deno version that was installed."
   is-canary:
     description: "If the installed Deno version was a canary version."
+  release-channel:
+    description: "The release channel of the installed version."
 runs:
   using: "node20"
   main: "main.js"