Use linuxdeploy action [skip ci]

I was going to try to build an arm64 and arm/v7 image using my new
linuxdeploy action at
https://github.com/andy5995/linuxdeploy-build-helper/, but I didn't get
a chance to fully test this because I can't get 0ad-0.0.26-alpha to
build on Ubuntu focal anymore (or maybe I built it on bionic last).

The SpiderMonkey build fails. The error message looks a bit different
than normal compiler errors, but I think this is the cause:

"ValueError: invalid literal for int() with base 16: 'file'"

Some Debian patches might fix the build:
https://packages.debian.org/bookworm/0ad

.github/workflows/appimage.yml

@@ -28,14 +28,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ubuntu_codename: ['focal', 'jammy']
-    container: andy5995/0ad-build-env:${{ matrix.ubuntu_codename }}
-    runs-on: ubuntu-22.04
+        platform: ['amd64']
+    runs-on: ubuntu-latest
     env:
-      ARCH: x86_64
-      WORKSPACE: ${{ github.workspace }}
-      VERSION: 0.0.27-rc1-27645-alpha
+      VERSION: 0.0.26-alpha
       UBUNTU_CODENAME: ${{ matrix.ubuntu_codename }}
+      MINISIGN_KEY: RWTWLbO12+ig3lUExIor3xd6DdZaYFEozn8Bu8nIzY3ImuRYQszIQyyy
     steps:
     - uses: actions/checkout@v4
     - name: Run Workflow script
@@ -50,18 +48,15 @@ jobs:
         name: 0ad-${{ env.VERSION }} AppImage
         allowUpdates: True
         prerelease: ${{ contains(env.VERSION, 'svn') || contains(env.VERSION, 'rc') }}
-        artifacts: "${{ env.WORKSPACE }}/0ad*.AppImage*"
+        artifacts: ./out/0ad*.AppImage*
         token: ${{ secrets.GITHUB_TOKEN }}
         omitNameDuringUpdate: True
         omitBodyDuringUpdate: True
         tag: v${{ env.VERSION }}
-        replacesArtifacts: true
+        replacesArtifacts: false
     - name: Upload Artifacts
       if: ${{ github.ref != 'refs/heads/trunk' }}
       uses: actions/upload-artifact@v4
       with:
-        name: AppImage
-        path: ${{ env.WORKSPACE }}/0ad*.AppImage*
-
-
-
+        name: AppImage-${{ matrix.platform }}
+        path: ./out/0ad*.AppImage*

Dockerfile-focal

@@ -46,16 +46,6 @@ RUN /bin/bash -c 'cd $TOOLS_DIR \
     && rm ./linuxdeploy-${ARCH}.AppImage \
     && cd -'
 
-ARG MINISIGN_VERSION="0.11"
-ENV MINISIGN_PATH=${TOOLS_DIR}/minisign
-ARG MINISIGN_URL=https://github.com/jedisct1/minisign/releases/download/${MINISIGN_VERSION}
-RUN /bin/bash -c 'curl -LO ${MINISIGN_URL}/minisign-${MINISIGN_VERSION}-linux.tar.gz \
-    && curl -LO ${MINISIGN_URL}/minisign-${MINISIGN_VERSION}-linux.tar.gz.minisig \
-    && tar xf minisign-${MINISIGN_VERSION}-linux.tar.gz -C ${TOOLS_DIR} \
-    && mv ${TOOLS_DIR}/minisign-linux/${ARCH}/minisign ${TOOLS_DIR} \
-    && $MINISIGN_PATH -Vm minisign-$MINISIGN_VERSION-linux.tar.gz -P RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3 \
-    && rm -rf ${TOOLS_DIR}/minisign-linux minisign-${MINISIGN_VERSION}-linux.tar.gz*'
-
 # For some reason, if '/home/0adbuilder' exists,
 # ./updateworkspaces.sh fails after the Collada
 # build, when the python virtual environment is created.

README.md

@@ -48,8 +48,7 @@ To speed up the process, prior to running the above script, copy the source
 and data archives (e.g., 0ad-0.0.26-alpha-unix-{build,data}.tar.xz) to the
 repo root (otherwise they'll be downloaded during the script execution).
 
-If choosing the svn version, the svn repository will be checked out, unless
-you aleady have it in the repo root.
+    SOURCE_ROOT=$(pwd)/0ad-0.0.26-alpha ./workflow.sh
 
 ## HOWTO change versions after a 0 A.D. release