Update changelog for 1.6.12-1 release

debian/changelog

+php-mikey179-vfsstream (1.6.12-1) unstable; urgency=medium
+
+  [ Jaapio ]
+  * Drop support for php 5
+  * Upgrade tests to run on newer phpunit
+  * Disable coverage for php 7.1
+
+  [ David Prévot ]
+  * Update Standards-Version to 4.7.0
+  * Don’t use yoast/phpunit-polyfills
+
+ -- David Prévot <taffit@debian.org>  Sun, 15 Sep 2024 12:33:53 +0200
+
 php-mikey179-vfsstream (1.6.11-1) unstable; urgency=medium
 
   * New upstream release