Update the TS typings

lib/gulp_plugin.d.ts

@@ -1,5 +1,4 @@
-import {Transform, TransformCallback} from "node:stream";
-import File from "vinyl"
+import {Transform} from "node:stream";
 
 /**
  * Minifies PHP source code by removing comments and whitespace.
@@ -11,15 +10,6 @@ export class GulpPlugin extends Transform {
 	 * @param options An object providing values to initialize this instance.
 	 */
 	constructor(options?: GulpPluginOptions);
-
-	/**
-	 * Transforms input and produces output.
-	 * @param chunk The chunk to transform.
-	 * @param encoding The encoding type if the chunk is a string.
-	 * @param callback The function to invoke when the supplied chunk has been processed.
-	 * @returns The transformed chunk.
-	 */
-	_transform(chunk: File, encoding: NodeJS.BufferEncoding, callback: TransformCallback): Promise<void>;
 }
 
 /**