Attempt #2 at using a newer ubuntu for build

- Try to fix invalid mount type "bind" for 'RUN --mount'

.github/workflows/build.yml

@@ -21,7 +21,7 @@ env:
 jobs:
   build_push_aurora:
     name: Build and publish SB image with ZFS
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
 
     permissions:
       contents: read

Containerfile

@@ -59,7 +59,8 @@ FROM ghcr.io/ublue-os/${SOURCE_IMAGE}${SOURCE_SUFFIX}:${SOURCE_TAG}
 
 COPY build.sh /tmp/build.sh
 
-RUN --mount=type=bind,from=kernel-cache,src=/tmp/rpms,dst=/tmp/rpms/kernel \
+RUN --mount=type=cache,dst=/var/cache/rpm-ostree \
+    --mount=type=bind,from=kernel-cache,src=/tmp/rpms,dst=/tmp/rpms/kernel \
     --mount=type=bind,from=zfs-cache,src=/rpms/kmods/zfs,dst=/tmp/rpms/zfs \
     mkdir -p /var/lib/alternatives && \
     /tmp/build.sh && \