dependabot: bump lycheeverse/lychee-action from 1.2.0 to 2.1.0

Bumps [lycheeverse/lychee-action](https://github.com/lycheeverse/lychee-action) from 1.2.0 to 2.1.0.
- [Release notes](https://github.com/lycheeverse/lychee-action/releases)
- [Commits](lycheeverse/lychee-action@v1.2.0...v2.1.0)

---
updated-dependencies:
- dependency-name: lycheeverse/lychee-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/links.yml

@@ -8,7 +8,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Lychee Link Checker
-        uses: lycheeverse/lychee-action@v1.2.0
+        uses: lycheeverse/lychee-action@v2.1.0
         with:
           args: --accept=200,403,429 **/*.html **/*.md **/*.txt **/*.json
           fail: true