docs: update link to Stylelint v14 migration guide

README.md

@@ -260,7 +260,7 @@ This extension contributes the following commands to the command palette:
 [stylelint]: https://stylelint.io/
 [stylelint getting started guide]: https://stylelint.io/user-guide/get-started
 [stylelint configuration file]: https://stylelint.io/user-guide/configuration
-[stylelint 14 migration guide]: https://github.com/stylelint/stylelint/blob/v14/docs/migration-guide/to-14.md
+[stylelint 14 migration guide]: https://github.com/stylelint/stylelint/blob/main/docs/migration-guide/to-14.md
 [`customsyntax`]: https://stylelint.io/user-guide/usage/options/#customsyntax
 [`config`]: https://stylelint.io/user-guide/usage/node-api#config
 [`configfile`]: https://stylelint.io/user-guide/usage/options#configfile