When using pnpm, pretest won't run by default

pnpm doesn't run pre/post scripts by default, and the template uses `pretest` which won't get invoked, even if you select pnpm as the package manager during generation. We should also generate an `.npmrc` with:
```npmrc
enable-pre-post-scripts = true
```

In such a case. See https://pnpm.io/cli/run#enable-pre-post-scripts