fix: using any instead of interface{} as per comment open-policy-agen…

…t#999 (comment)

Signed-off-by: Punith C K <[email protected]>

policy/engine.go

@@ -224,7 +224,7 @@ func (e *Engine) Namespaces() []string {
 // Documents returns all of the documents loaded into the engine.
 // The result is a map where the key is the filepath of the document
 // and its value is the raw contents of the loaded document.
-func (e *Engine) Documents() map[string]interface{} {
+func (e *Engine) Documents() map[string]any {
 	return e.docs
 }