Create GitHub action to generate PDF of Surge XT Manual

.github/workflows/surge-xt-manual-pdf.yml

@@ -0,0 +1,44 @@
+name: Surge XT Manual PDF
+
+on:
+  push:
+    paths:
+      - 'manual_xt/**'
+  pull_request:
+    paths:
+      - 'manual_xt/**'
+
+permissions:
+  contents: write
+
+jobs:
+  Surge-XT-Manual-PDF:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Build PDF
+        run: >
+          wget -q https://github.com/jgm/pandoc/releases/download/2.18/pandoc-2.18-1-amd64.deb;
+          sudo apt install ./pandoc-2.18-1-amd64.deb;
+          wget -q https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.focal_amd64.deb;
+          sudo apt install ./wkhtmltox_0.12.6-1.focal_amd64.deb;
+          cd manual_xt;
+          pandoc -f gfm -t html Surge-XT.md -o Surge-XT-Manual.pdf
+          --css pdf.css -V title:""
+          --pdf-engine-opt="--footer-font-name" --pdf-engine-opt="Lato"
+          --pdf-engine-opt="--footer-font-size" --pdf-engine-opt="12"
+          --pdf-engine-opt="--footer-center" --pdf-engine-opt="[page]/[topage]"
+          --pdf-engine-opt="--no-footer-line" --pdf-engine-opt="--footer-spacing" --pdf-engine-opt="5"
+          --pdf-engine-opt="--disable-smart-shrinking"
+          --pdf-engine-opt="--zoom" --pdf-engine-opt="1"
+
+      - name: Release
+        uses: softprops/action-gh-release@v0.1.14
+        with:
+          tag_name: surge-xt-manual
+          name: Surge XT Manual
+          body: PDF of the [Surge XT Manual](https://surge-synthesizer.github.io/manual-xt/)
+          files: |
+            manual_xt/Surge-XT-Manual.pdf