v2.2.0-rc.2

Edit: Don't use rc2, use rc3 instead. (Released just a few hours later as a hotfix.)

The next release candidate for v2.2.0 - please try it out before the final tag! As always, deploy into a test or staging environment before production.

There are a lot of commits in this release because the milestone moved while we fixed problems that were reported, and we also wanted to make sure the final v2.2 release will be good and solid. Most of these commits are bug fixes, but we've also added Caddyfile support for several features, and notably: integrated Prometheus metrics. (Thanks @hairyhenderson and other contributors! That was a team effort.)

As you might expect, this release builds on all changes in RC1.

The documentation on our website will be updated after the final release is tagged.

Changelog

d4f2497 browse: align template to struct field renames from 4940325 (#3706)
b01bb27 caddyhttp: New placeholder for PEM of client certificate (#3662)
04f50a9 caddyhttp: Wrap http.Server logging with zap (#3668)
00e6b77 caddytls: Add dns config to acmeissuer (#3701)
744d04c caddytls: Configure custom DNS resolvers for DNS challenge (close #2476)
24f3478 caddytls: Customize DNS resolvers for DNS challenge with Caddyfile
9859ab8 caddytls: Fix resolvers option of acme issuer (Caddyfile)
b88e2b6 cmd: Allow caddy fmt to read from stdin (#3680)
4940325 fileserver: Fix inconsistencies in browse JSON
1c5969b fileserver: Fix new file hide tests on Windows (#3719)
b95b873 fileserver: Fix try_files for directories; windows fix (#3684)
0ee4378 fileserver: Improve file hiding logic for directories and prefixes
3ee663d go.mod: Upgrade dependencies
997ef52 go.mod: Use v0.15(.1) of smallstep libs
e3324aa httpcaddyfile: Ensure handle_path is sorted equally to handle (#3676)
0afbab8 httpcaddyfile: Improve directive sorting logic (#3658)
4217217 httpcaddyfile: Properly record whether we added catch-all conn policy
309c1fe logging: Implement Caddyfile support for filter encoder (#3578)
8ec51bb metrics: Initial integration of Prometheus metrics (#3709)
724b74d reverseproxy: Abort active health checks on context cancellation
4cd7ae3 reverseproxy: Add buffer_requests option to reverse_proxy directive (#3710)
bc453fa reverseproxy: Correct alternate port for active health checks (#3693)
d55d50b reverseproxy: Enforce port range size of 1 at provision (#3695)
c94f5bb reverseproxy: Make default buffer size const
fc65320 reverseproxy: Support header selection policy on Host field (#3653)