deprecate: mode (#325)

* test: add tests for context

* deprecate: mode

* revert docs for deprecated option

src/types/core.ts

@@ -10,8 +10,9 @@ export interface Wrapper {
     events?: string;
     /**
      * Overload to enable mode in case developer does not use a .env file.
+     * @deprecated - https://github.com/sern-handler/handler/pull/325
      */
-    mode?: 'DEV' | 'PROD';
+    mode?: string
     /*
      * @deprecated
      */