make-release.py: Updated release notes and changelog for 1.0.12.

contrib/debian/changelog

@@ -1,3 +1,9 @@
+zcash (1.0.12) stable; urgency=medium
+
+  * 1.0.12 release.
+
+ -- Zcash Company <team@z.cash>  Thu, 28 Sep 2017 01:26:44 +0100
+
 zcash (1.0.12~rc1) stable; urgency=medium
 
   * 1.0.12-rc1 release.

doc/authors.md

@@ -1,8 +1,8 @@
 Zcash Contributors
 ==================
 
-Jack Grigg (465)
-Simon Liu (272)
+Jack Grigg (470)
+Simon Liu (274)
 Sean Bowe (188)
 Daira Hopwood (102)
 Taylor Hornby (65)

doc/release-notes/release-notes-1.0.12.md

@@ -0,0 +1,14 @@
+Changelog
+=========
+
+Jack Grigg (5):
+      Fix pyflakes warnings in RPC tests
+      Individualise performance-measurements.sh errors for debugging
+      Fix incorrect failure in memory benchmark
+      make-release.py: Versioning changes for 1.0.12.
+      make-release.py: Updated manpages for 1.0.12.
+
+Simon Liu (2):
+      Update which lock to synchronize on when calling GetBestAnchor().
+      Closes #2637. Make z_shieldcoinbase an experimental feature where it     can be enabled with: zcashd -experimentalfeatures -zshieldcoinbase.
+