Fill in release date for 2.7

CHANGELOG.txt

@@ -12,7 +12,7 @@ Changelog
  * Fix: Submenu items longer then the page height are no longer broken by the submenu footer (Igor van Spengen)
  * Fix: Unbundle the l18n library as it was bundled to avoid installation errors which have been resolved (Matt Westcott)
 
-2.7 LTS (xx.xx.xxxx) - IN DEVELOPMENT
+2.7 LTS (06.11.2019)
 ~~~~~~~~~~~~~~~~~~~~
 
  * Improved StreamField design (Bertrand Bordage)

docs/releases/2.7.rst

@@ -1,6 +1,6 @@
-==========================================
-Wagtail 2.7 release notes - IN DEVELOPMENT
-==========================================
+=========================
+Wagtail 2.7 release notes
+=========================
 
 .. contents::
     :local: