Prepare release: (#3614)

* run Makefile.doc to update to the latest
* add prs and authors to Makefile.release to aid in creating release
  notes. And update the comments in the makefile.
* add 1.6.7 release notes.

Signed-off-by: Miek Gieben <miek@miek.nl>

notes/coredns-1.6.7.md

@@ -0,0 +1,41 @@
++++
+title = "CoreDNS-1.6.7 Release"
+description = "CoreDNS-1.6.7 Release Notes."
+tags = ["Release", "1.6.7", "Notes"]
+release = "1.6.7"
+date = 2020-01-24T10:00:00+00:00
+author = "coredns"
++++
+
+The CoreDNS team has released
+[CoreDNS-1.6.7](https://github.com/coredns/coredns/releases/tag/v1.6.7).
+
+This is a fairly small release that resolves some nits and it adds mips64le to the set of
+architectures that we create binaries for. See "Noteworthy Changes" for more detail.
+
+## Brought to You By
+
+Antonio Ojea,
+Brad P. Crochet,
+Dominic Yin,
+DrmagicE,
+Erfan Besharat,
+Jonathan Nagy,
+Kohei Yoshida,
+Miek Gieben,
+Yong Tang,
+Zheng Xie,
+Zou Nengren.
+
+## Noteworthy Changes
+
+* Add mips64le to released architectures (https://github.com/coredns/coredns/pull/3589)
+* Fix HostPortOrFile to support IPv6 addresses with zone (https://github.com/coredns/coredns/pull/3527)
+* plugin/acl: Document metrics in README (https://github.com/coredns/coredns/pull/3605)
+* plugin/cache: Registry cache_miss logic (https://github.com/coredns/coredns/pull/3578)
+* plugin/cache: Update comment to conform to the implementation (https://github.com/coredns/coredns/pull/3573)
+* plugin/{forward, grpc}: Dedup policy implement between grpc and proxy plugin (https://github.com/coredns/coredns/pull/3537)
+* plugin/kubernetes: Bump kubernetes plugin schema version (https://github.com/coredns/coredns/pull/3554)
+* plugin/{kubernetes, etc}: Resolve TXT records via CNAME (https://github.com/coredns/coredns/pull/3557)
+* plugin/logs: Docs: update README and log plugin (https://github.com/coredns/coredns/pull/3602)
+* plugin/sign: Add expiration jitter (https://github.com/coredns/coredns/pull/3588)