Remove unused worker

src/ol/worker/version.js

@@ -1,15 +0,0 @@
-/**
- * A worker that responds to messages by posting a message with the version identifier.
- * @module ol/worker/version
- */
-import {VERSION} from '../util.js';
-
-/** @type {any} */
-const worker = self;
-
-worker.onmessage = (event) => {
-  console.log('version worker received message:', event.data); // eslint-disable-line
-  worker.postMessage(`version: ${VERSION}`);
-};
-
-export let create;