.github: publish .pkg bundle and Raspberry Pi image on release

Releases exposed the RAUC upgrade bundle only inside the per-arch
tarball, and shipped no ready-to-flash Raspberry Pi image; users had
to unpack the tarball or assemble an image from a separate bootloader.

Upload output/images/*.pkg as its own artifact, and build an rpi64 SD
card image in the aarch64 release leg before rootfs.squashfs is
stripped from the tarball, combining it with the rpi64 bootloader from
the latest-boot release.  Publish both as release assets; the tarball
still carries the .pkg too.

Closes #1084

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

.github/workflows/build-release.yml

@@ -70,6 +70,25 @@ jobs:
         run: |
           make test-spec
 
+      # rootfs.squashfs is still present here; it is stripped from the
+      # tarball below.  mkimage pulls the rpi64 bootloader from the
+      # latest-boot release and uses the freshly built host genimage.
+      - name: Build Raspberry Pi image
+        if: matrix.target == 'aarch64'
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          ./utils/mkimage.sh -d -r output raspberrypi-rpi64
+          mkdir -p rpi-image
+          mv output/images/*-rpi64-sdcard.img rpi-image/
+          xz -T0 rpi-image/*-rpi64-sdcard.img
+
+      - uses: actions/upload-artifact@v7
+        if: matrix.target == 'aarch64'
+        with:
+          name: artifact-rpi64-image
+          path: rpi-image/*.img.xz
+
       - name: Prepare Artifacts
         run: |
           cd output/
@@ -98,3 +117,8 @@ jobs:
         with:
           name: artifact-disk-image-${{ matrix.target }}
           path: output/images/*.qcow2
+
+      - uses: actions/upload-artifact@v7
+        with:
+          name: artifact-pkg-${{ matrix.target }}
+          path: output/images/*.pkg

.github/workflows/release.yml

@@ -95,7 +95,7 @@ jobs:
           makeLatest: ${{ steps.rel.outputs.latest }}
           discussionCategory: ${{ steps.rel.outputs.cat }}
           bodyFile: release.md
-          artifacts: "*.tar.gz,*.qcow2"
+          artifacts: "*.tar.gz,*.qcow2,*.pkg,*.img.xz"
 
       - name: Summary
         run: |