Rename release record folder to 006-go-1-27

Folder names may only use lowercase letters, digits and hyphens;
TestEmbeddedReleasesAllLoad caught the dots.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pull-releases/README.md

@@ -32,4 +32,4 @@ screenshot, or its `README.md` doesn't load.
 | [003](003-css-cache-busting/) | Content hash on the stylesheet URL; this folder |
 | [004](004-release-notes-page/) | Release notes pages on the site |
 | [005](005-post-author/) | Author in the post header |
-| [006](006-go-1.27/) | Require Go 1.27.3 (security fixes) |
+| [006](006-go-1-27/) | Require Go 1.27.3 (security fixes) |