Enable vale for prose linting (#3)

* Enable vale in CI

* Add vale config

* Tweak vale

* Update config

* Update .gitignore

* Switch back

* Rename CI

* Add badges

* Tidy up CI

* Change image

* Configure vale

* Delint

* Update README

.github/workflows/continuous_delivery.yaml

@@ -0,0 +1,35 @@
+name: Continuous Delivery
+
+on:
+  workflow_dispatch:
+
+jobs:
+  pdf:
+    runs-on: ubuntu-latest
+    container:
+      image: asciidoctor/docker-asciidoctor
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Generate PDF
+        run: make output/book.pdf
+      - name: Archive PDF
+        uses: actions/upload-artifact@v4
+        with:
+          name: pdf
+          path: output/book.pdf
+  epub:
+    runs-on: ubuntu-latest
+    container:
+      image: asciidoctor/docker-asciidoctor
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Generate EPUB
+        run: make output/book.epub
+      - name: Archive EPUB
+        uses: actions/upload-artifact@v4
+        with:
+          name: epub
+          path: output/book.epub
+