add release workflow

.github/workflows/release.yml

@@ -0,0 +1,77 @@
+name: Package and push to registry repo
+on:
+  push:
+    tags: [ v* ]
+
+env:
+  # the repository to which to push the release version
+  # usually a fork of typst/packages (https://github.com/typst/packages/)
+  # that you have push privileges to
+  REGISTRY_REPO: author/typst-packages
+  # the path within that repo where the "<name>/<version>" directory should be put
+  # for the Typst package registry, keep this as is
+  PATH_PREFIX: packages/preview
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Probe runner package cache
+        uses: awalsh128/cache-apt-pkgs-action@v1
+        with:
+          packages: cargo
+          version: 1.0
+
+      - name: Install just from crates.io
+        uses: baptiste0928/cargo-install@v3
+        with:
+          crate: just
+
+      - name: Setup typst
+        uses: typst-community/setup-typst@v3
+        with:
+          typst-version: latest
+
+      - name: Determine and check package metadata
+        run: |
+          . scripts/setup
+          echo "PKG_NAME=${PKG_PREFIX}" >> "${GITHUB_ENV}"
+          echo "PKG_VERSION=${VERSION}" >> "${GITHUB_ENV}"
+
+          if [[ "${GITHUB_REF_NAME}" != "v${VERSION}" ]]; then
+            echo "package version ${VERSION} does not match release tag ${GITHUB_REF_NAME}" >&2
+            exit 1
+          fi
+
+      - name: Build package
+        run: |
+          just doc
+          just package out
+
+      - name: Checkout package registry
+        uses: actions/checkout@v4
+        with:
+          repository: ${{ env.REGISTRY_REPO }}
+          token: ${{ secrets.REGISTRY_TOKEN }}
+          path: typst-packages
+
+      - name: Release package
+        run: |
+          mkdir -p "typst-packages/${{ env.PATH_PREFIX }}/$PKG_NAME"
+          mv "out/${PKG_NAME}/${PKG_VERSION}" "typst-packages/${{ env.PATH_PREFIX }}/${PKG_NAME}"
+          rmdir "out/${PKG_NAME}"
+          rmdir out
+
+          GIT_USER_NAME="$(git log -1 --pretty=format:'%an')"
+          GIT_USER_EMAIL="$(git log -1 --pretty=format:'%ae')"
+
+          cd typst-packages
+          git config user.name "${GIT_USER_NAME}"
+          git config user.email "${GIT_USER_EMAIL}"
+          git checkout -b "${PKG_NAME}-${PKG_VERSION}"
+          git add .
+          git commit -m "${PKG_NAME}:${PKG_VERSION}"
+          git push --set-upstream origin "${PKG_NAME}-${PKG_VERSION}"