release: prepare v7.0.0

I documented the CommonMarker compatibility changes, RDoc 8 support, and reStructuredText anchor fixes since v6.0.0. I updated the package version without changing locked dependencies.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 6fe372b1-3ff6-4129-9d33-be564fb6a5f0
Signed-off-by: Zack Koppert <zkoppert@github.com>

Author: zkoppert

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    github-markup (6.0.0)
+    github-markup (7.0.0)
       rdoc (< 9)
 
 GEM

HISTORY.md

@@ -1,3 +1,20 @@
+## 7.0.0 - 2026-10-15
+
+### Breaking
+
+* Require commonmarker 2.x when using the CommonMarker renderer; upgrade existing commonmarker 0.x installations [#2059](https://github.com/github/markup/pull/2059).
+* Accept `VALIDATE_UTF8`, `LIBERAL_HTML_TAG`, `TABLE_PREFER_STYLE_ATTRIBUTES`, and `STRIKETHROUGH_DOUBLE_TILDE` without applying them [#2059](https://github.com/github/markup/pull/2059).
+
+### Bug Fixes
+
+* Support RDoc 8 formatter initialization and declare `rdoc < 9` as a runtime dependency [#2109](https://github.com/github/markup/pull/2109), [#2104](https://github.com/github/markup/pull/2104).
+* Restore reStructuredText section and table-of-contents anchors with docutils 0.18 and later [#2081](https://github.com/github/markup/pull/2081), [#2087](https://github.com/github/markup/pull/2087).
+
+### Development
+
+* Update development dependencies to commonmarker 2.8.2, html-pipeline 3.2, minitest 6, and activesupport 8.1.
+* Require 100% measured line and branch coverage and load gem metadata without loading renderers [#2072](https://github.com/github/markup/pull/2072).
+
 ## 6.0.0 - 2026-05-04
 
 ### Breaking

lib/github-markup.rb

@@ -1,6 +1,6 @@
 module GitHub
   module Markup
-    VERSION = '6.0.0'
+    VERSION = '7.0.0'
     Version = VERSION
   end
 end