ci: Add Vale github action

Signed-off-by: Bobby Eshleman <bobby.eshleman@gmail.com>

Author: beshleman

.github/workflows/vale.yml

@@ -0,0 +1,14 @@
+---
+name: Linting
+on: [push]
+
+jobs:
+  style:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@master
+      - name: Style
+        uses: xcp-ng/vale-styles@v0.1
+        with:
+          files: docs/*

.vale.ini

@@ -0,0 +1,7 @@
+StylesPath = .github/styles/
+MinAlertLevel = suggestion
+
+# Only Markdown files;
+[*.{md}]
+# List of styles to load.
+BasedOnStyles = gitlab, vates