dehydrated: critical bump to 0.6.5

On July 3, 2019, Let's Encrypt deployed new ACME server software that no
longer returns the 'id' field in the account information JSON.
Dehydrated relied on this field, even though it is not specified by RFC
8555. Because of this, dehydrated can no longer create a new account on
Let's Encrypt.

This was fixed by upstream commits be13dcd and 4f358e2. But the latter
broke ACMEv1 support so was fixed again in commit f60f2f8.

Cherry-picking this correctly is tricky, so instead just bump the
version. There are quite a few non-bugfix changes that are included this
way, but it's more risky to try to cherry-pick.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>