Update ACME to 0.21

[buchdag]

A few more changes than usual:

• acme.jose has been moved to a separate package named josepy
• python 2.6 is being deprecated by acme like 3.3 was last year

[hugovk]

Oh, in setup.py, the "sys.version_info < (2, 7):" part can also be cleaned up, and 'Programming Language :: Python :: 2.6' could be removed.

[zenhack]

Quoting Hugo (2018-01-19 14:39:12)

Oh, in setup.py, the "sys.version_info < (2, 7):" part can also be cleaned up, and 'Programming Language :: Python :: 2.6' could be removed.

Good call; let's get that done while we're at it.

[buchdag]

✅ Done.

(order of the commits has been changed, changelog update is now last).

[zenhack]

One minor thing. Sorry such a small patch is taking so much back and forth.

[buchdag]

Sorry such a small patch is taking so much back and forth.

Don't, removing mock from install_requires was me not paying attention.

[zenhack]

LGTM