Adds an option to do lookup-only of the cache (#217)

action.yml

@@ -40,6 +40,10 @@ inputs:
     description: "Determines which provider to use for caching. Options are github or buildjet, defaults to github."
     required: false
     default: "github"
+  lookup-only:
+    description: "Check if a cache entry exists without downloading the cache"
+    required: false
+    default: "false"
 outputs:
   cache-hit:
     description: "A boolean value that indicates an exact match was found."