Remove deprecated Staticman v1 config

Close #2386

test/_config.yml

@@ -37,23 +37,9 @@ comments:
   utterances:
     theme                : # "github-light" (default), "github-dark"
     issue_term           : # "pathname" (default)
-staticman:
-  allowedFields          : ['name', 'email', 'url', 'message']
-  branch                 : # "master", "gh-pages"
-  commitMessage          : "New comment by {fields.name}"
-  filename               : comment-{@timestamp}
-  format                 : "yml"
-  moderation             : true
-  path                   : "_data/comments/{options.slug}"
-  requiredFields         : ['name', 'email', 'message']
-  transforms:
-    email                : "md5"
-  generatedFields:
-    date:
-      type               : "date"
-      options:
-        format           : "iso8601" # "iso8601" (default), "timestamp-seconds", "timestamp-milliseconds"
-  endpoint               : # URL of your own deployment with trailing slash, will fallback to the public instance
+  staticman:
+    branch               : # "master"
+    endpoint             : # "https://{your Staticman v3 API}/v3/entry/github/"
 atom_feed:
   path                   : # blank (default) uses feed.xml
 search                   : true # true, false (default)