e2e: use latest version of Yarn 2 when running tests

Using `latest` keyword with yarn 1 resolves to Yarn 1.x but we need Yarn 2.

scripts/run-e2e.ts

@@ -78,7 +78,7 @@ const cleanDirectory = async ({ cwd }: Options): Promise<void> => {
 
 const configureYarn2 = async ({ cwd }: Options) => {
  const command = [
- `yarn set version 2`,
+ `yarn set version berry`,
  // ⚠️ Need to set registry because Yarn 2 is not using the conf of Yarn 1
  `yarn config set npmScopes --json '{ "storybook": { "npmRegistryServer": "http://localhost:6000/" } }'`,
  // Some required magic to be able to fetch deps from local registry