Add doc validation workflow

Author: josbeir

.github/workflows/docs-validation.yml

@@ -0,0 +1,26 @@
+name: Documentation Validation
+
+on:
+  push:
+    branches:
+      - 4.x
+    paths:
+      - 'docs/**'
+      - '.github/**'
+  pull_request:
+    paths:
+      - 'docs/**'
+      - '.github/**'
+
+jobs:
+  validate:
+    uses: cakephp/.github/.github/workflows/docs-validation.yml@doc-workflows
+    with:
+      docs-path: 'docs'
+      enable-config-js-check: true
+      enable-json-lint: true
+      enable-toc-check: true
+      enable-spell-check: true
+      enable-markdown-lint: true
+      enable-link-check: true
+      tools-ref: 'doc-workflows'