Lock yarn pnp version in tests

Author: ijjk

test/e2e/yarn-pnp/test/utils.ts

@@ -31,7 +31,7 @@ export function runTests(example = '') {
           prev.push(`${cur}@${dependencies[cur]}`)
           return prev
         }, [] as string[])
-        return `yarn set version berry && yarn config set enableGlobalCache true && yarn config set compressionLevel 0 && yarn add ${pkgs.join(
+        return `yarn set version 3.1.1 && yarn config set enableGlobalCache true && yarn config set compressionLevel 0 && yarn add ${pkgs.join(
           ' '
         )}`
       },