Re-add strict peer dependencies

[julrich]

Those were disabled in the imminent release of the new major version, because of hassle with unreleased versions, canaries, etc.

Should be re-enabled when everything is released cleanly, because we should still strive for strict peer dependencies!

Change was introduced here:
3c40b3c#diff-28e9074e25bc23ee331727eee3ce66d83d4e59101d0b740b362b1d23ab10bfff