refactor(tests): use `hyperlink` rather than `htmltest` for link checking

It's very fast, only checks internal links, and it's easy to use.

.github/workflows/deploy.yml

@@ -39,12 +39,7 @@ jobs:
         run: pdm run build
 
       - name: Check for broken internal links
-        uses: wjdp/htmltest-action@master
-        with:
-          path: _htdocs
-          config: .htmltest.yml
-          skip_external: true
-          log_level: 1
+        run: pdm run check-links
 
       - name: Deploy lektor website
         if: env.DEPLOY == 'true'

pyproject.toml

@@ -35,3 +35,5 @@ _.env = {LEKTOR_OUTPUT_PATH = "_htdocs"}
 build  = "lektor build -f webpack"
 server = "lektor server -f webpack"
 deploy = "lektor deploy ghpages-https"
+
+check-links = "npx --yes @untitaker/hyperlink@~0.1.32 --check-anchors _htdocs"