release: prepare v6.1.0 replacement (#2113)

I reclassified the withdrawn `v7.0.0` release as `v6.1.0` while keeping the same renderer behavior and dependency requirements. I retained the documented compatibility changes and marked the historical `v7.0.0` entry withdrawn.

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

Author: zkoppert

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    github-markup (7.0.0)
+    github-markup (6.1.0)
       rdoc (< 9)
 
 GEM

HISTORY.md

@@ -1,4 +1,27 @@
-## 7.0.0 - 2026-10-15
+## 6.1.0 - 2026-10-16
+
+Version `6.1.0` replaces the withdrawn `7.0.0` release with the same runtime behavior and dependency requirements. The CommonMarker compatibility changes below remain in effect.
+
+### Compatibility Changes
+
+* 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).
+* Preserve soft line breaks with `NOBREAKS` instead of converting them to spaces [#2059](https://github.com/github/markup/pull/2059).
+* Apply `HARDBREAKS` and `NOBREAKS` in their supplied order; the last flag wins, replacing the old `HARDBREAKS` precedence [#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).
+
+## 7.0.0 - 2026-10-15 (withdrawn)
+
+I withdrew this release on 2026-10-16. The `v7.0.0` tag remains available for traceability.
 
 ### Breaking
 

lib/github-markup.rb

@@ -1,6 +1,6 @@
 module GitHub
   module Markup
-    VERSION = '7.0.0'
+    VERSION = '6.1.0'
     Version = VERSION
   end
 end