fix: remove the browser entry from package.json

When this entry is in, webpack never picks up on the module one,
which makes it go the wrong way. Since VTU is meant to be used in
Jest/Webpack/Rollup/Vite we shuold avoid breaking those.

I matched the exports of vue and vite here.

Author: elevatebart

package.json

@@ -3,7 +3,6 @@
   "version": "2.0.0-rc.0",
   "license": "MIT",
   "main": "dist/vue-test-utils.cjs.js",
-  "browser": "dist/vue-test-utils.browser.js",
   "unpkg": "dist/vue-test-utils.browser.js",
   "types": "dist/index.d.ts",
   "module": "dist/vue-test-utils.esm-bundler.js",