Update dependency markdownlint-cli2 to v0.18.0 (#296)

| datasource | package           | from   | to     |
| ---------- | ----------------- | ------ | ------ |
| npm        | markdownlint-cli2 | 0.17.2 | 0.18.0 |

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

setup/markdownlint/package-lock.json

@@ -2,6 +2,6 @@
   "name": "laminas-continuous-integration-action-markdownlint",
   "description": "Frozen dependencies required for installing a stable \\`markdownlint\\` binary",
   "dependencies": {
-    "markdownlint-cli2": "0.17.2"
+    "markdownlint-cli2": "0.18.0"
   }
 }