Update README.md to include usage

Adds examples to the `usage` section of the README

README.md

@@ -2,15 +2,73 @@
 
 A simple GitHub Action for producing Jekyll build artifacts compatible with GitHub Pages.
 
-# Scope
+## Scope
 
 This is used along with [`actions/deploy-pages`](https://github.com/actions/deploy-pages) as part of the official support for building Pages with Actions (currently in public beta for public repositories).
 
-# Usage
+## Usage
 
-See [action.yml](action.yml)
+A basic workflow with the `jekyll-build-pages` action looks like this.
 
-# Release instructions
+```yaml
+name: Build Jekyll site
+on:
+ push:
+   branches: ["main"]
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Setup Pages
+        uses: actions/configure-pages@v3
+      - name: Build
+        uses: actions/jekyll-build-pages@v1
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v1
+  deploy:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v2
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+```
+
+To write to a different destination directory, match the inputs of both the `jekyll-build-pages` and `upload-pages-artifact` actions.
+
+```yaml
+steps:
+  - name: Build
+    uses: actions/jekyll-build-pages@v1
+    with:
+      destination: "./output"
+  - name: Upload artifact
+    uses: actions/upload-pages-artifact@v1
+    with:
+      path: "./output"
+```
+
+### Action inputs
+
+| Input | Default | Description |
+|-------|---------|-------------|
+| `source` | `./` | The directory to build from |
+| `destination` | `./_site` | The directory to write output into<br>(this should match the `path` input of the `actions/upload-pages-artifact` action) |
+| `future` | `false` | If `true`, writes content dated in the future |
+| `build_revision` | `$GITHUB_SHA` | The SHA-1 of the Git commit for which the build is running |
+| `verbose` | `false` | If `true`, prints verbose output in logs |
+| `token` | `$GITHUB_TOKEN` | The GitHub token used to authenticate API requests |
+
+## Release instructions
 
 In order to release a new version of this Action: