By default, do not link check.

Link checker is enabled via ENABLED_HTMLPROOFER=true by the check-links
script

doc.zih.tu-dresden.de/mkdocs.yml

@@ -226,8 +226,8 @@ plugins:
   # https://github.com/manuzhang/mkdocs-htmlproofer-plugin
   - htmlproofer:
       # True by default
-      # Toggle via env. var. ENABLED_HTMLPROOFER=false
-      enabled: !ENV [ENABLED_HTMLPROOFER, True]
+      # Enable via env. var. ENABLED_HTMLPROOFER=true
+      enabled: !ENV [ENABLED_HTMLPROOFER, False]
       # Check URLs before serving. Raise error and fail build at first bad URL.
       # raise_error: !ENV [ENABLED_HTMLPROOFER_RE, False]
       # Raise error and fail build after all URLs have been checked.