Create spec update flow

Author: kmonsen

.github/workflows/spec-update.yml

@@ -0,0 +1,29 @@
+name: Spec Update
+on:
+  workflow_dispatch: {}
+  pull_request: {}
+  push:
+    branches: [main]
+jobs:
+  main:
+    name: Build, Validate and Deploy
+    runs-on: ubuntu-20.04
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v3
+      - uses: w3c/spec-prod@v2
+        with:
+          TOOLCHAIN: bikeshed
+
+          # Modify as appropriate
+          GH_PAGES_BRANCH: gh-pages
+
+          # if your doc isn't in the root folder,
+          # or Bikeshed otherwise can't find it:
+          SOURCE: spec.bs
+
+          # output filename defaults to your input
+          # with .html extension instead,
+          # but if you want to customize it:
+          DESTINATION: index.html