update markdown linter

Author: sheenamt

.pre-commit-config.yaml

@@ -12,7 +12,7 @@ repos:
       - id: trailing-whitespace
 
   - repo: git://github.com/igorshubovych/markdownlint-cli
-    rev: v0.26.0
+    rev: v0.28.1
     hooks:
       - id: markdownlint