Remove v in version and add locateFile func to fix worker script issue

Author: jeromewu

src/browser/defaultOptions.js

@@ -7,5 +7,5 @@ const { devDependencies } = require('../../package.json');
 module.exports = {
   corePath: (typeof process !== 'undefined' && process.env.FFMPEG_ENV === 'development')
     ? resolveURL('/node_modules/@ffmpeg/core/dist/ffmpeg-core.js')
-    : `https://unpkg.com/@ffmpeg/core@v${devDependencies['@ffmpeg/core'].substring(1)}/dist/ffmpeg-core.js`,
+    : `https://unpkg.com/@ffmpeg/core@${devDependencies['@ffmpeg/core'].substring(1)}/dist/ffmpeg-core.js`,
 };

src/createFFmpeg.js

@@ -53,6 +53,14 @@ module.exports = (_options = {}) => {
       Core = await createFFmpegCore({
         printErr: (message) => parseMessage({ type: 'fferr', message }),
         print: (message) => parseMessage({ type: 'ffout', message }),
+        locateFile: (path, prefix) => {
+          if (typeof window !== 'undefined'
+            && typeof window.FFMPEG_CORE_WORKER_SCRIPT !== 'undefined'
+            && path.endsWith('ffmpeg-core.worker.js')) {
+            return window.FFMPEG_CORE_WORKER_SCRIPT;
+          }
+          return prefix + path;
+        },
       });
       ffmpeg = Core.cwrap('proxy_main', 'number', ['number', 'number']);
       log('info', 'ffmpeg-core loaded');