Test/link checker extension

package.json

@@ -7,7 +7,7 @@
   "scripts": {
     "build": "antora --to-dir docs --fetch antora-playbook.yml && cp _redirects docs",
     "build-local": "antora --to-dir docs --fetch antora-playbook-local.yml",
-    "check-links-local": "antora --fetch --to-dir test --log-level=error --log-failure-level=error --extension=./lib/antora-link-checker-extension.js antora-playbook-local.yml",
+    "check-links-local": "antora --fetch --to-dir test --log-level=warn --log-failure-level=warn --extension=./lib/antora-link-checker-extension.js antora-playbook-local.yml",
     "generate-pdfs-platform-5-5": "antora assembler-playbook-platform-5-5.yml",
     "generate-pdfs-platform-5-4": "antora assembler-playbook-platform-5-4.yml",
     "generate-pdfs-platform-5-3": "antora assembler-playbook-platform-5-3.yml",