[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/markdownlint/markdownlint: v0.12.0 → v0.15.0](markdownlint/markdownlint@v0.12.0...v0.15.0)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -9,7 +9,7 @@ repos:
     -   id: trailing-whitespace
 
 - repo: https://github.com/markdownlint/markdownlint
-  rev: v0.12.0
+  rev: v0.15.0
   hooks:
   - id: markdownlint
     args: ["-r", "~MD013"]