[Certbot-dev] Certbot 0.26.0

[Brad Warren]

Certbot 0.26.0 has been released. The change log for the release is:

## 0.26.0 - 2018-07-11

### Added

* A new security enhancement which we're calling AutoHSTS has been added to Certbot's Apache plugin. This enhancement configures your webserver to send a HTTP Strict Transport Security header with a low max-age value that is slowly increased over time. The max-age value is not increased to a large value until you've successfully managed to renew your certificate. This enhancement can be requested with the --auto-hsts flag.
* New official DNS plugins have been created for Gehirn Infrastracture Service, Linode, OVH, and Sakura Cloud. These plugins can be found on our Docker Hub page at https://hub.docker.com/u/certbot and on PyPI.
* The ability to reuse ACME accounts from Let's Encrypt's ACMEv1 endpoint on Let's Encrypt's ACMEv2 endpoint has been added.
* Certbot and its components now support Python 3.7. 
* Certbot's install subcommand now allows you to interactively choose which certificate to install from the list of certificates managed by Certbot.
* Certbot now accepts the flag `--no-autorenew` which causes any obtained certificates to not be automatically renewed when it approaches expiration.
* Support for parsing the TLS-ALPN-01 challenge has been added back to the acme library.

### Changed

* Certbot's default ACME server has been changed to Let's Encrypt's ACMEv2 endpoint. By default, this server will now be used for both new certificate lineages and renewals.
* The Nginx plugin is no longer marked labeled as an "Alpha" version.
* The `prepare` method of Certbot's plugins is no longer called before running "Updater" enhancements that are run on every invocation of `certbot renew`.

Despite us having broken lockstep, we are continuing to release new versions of all Certbot components during releases for the time being, however, the only packages with functional changes were:

* acme
* certbot
* certbot-apache
* certbot-dns-gehirn
* certbot-dns-linode
* certbot-dns-ovh
* certbot-dns-sakuracloud
* certbot-nginx

More details about these changes can be found on our GitHub repo:
https://github.com/certbot/certbot/milestone/55?closed=1