fix: update comment

Author: dukeluo

lib/rules/filename-blocklist.js

@@ -61,6 +61,7 @@ module.exports = {
         )) {
           const matchResult =
             matchRule(filenameWithPath, blockListPattern) ||
+            // TODO: remove this in next major version
             // legacy support for versions <= 2.0.0
             // file only can be specified by its filename, not by file path pattern
             // it's a legacy feature, will be removed in the future