tools/build-release.sh: don't assume you need sudo to run docker.

diff --git a/doc/contribute-to-core-lightning/release-checklist.md b/doc/contribute-to-core-lightning/release-checklist.md
index 1ca3e669..624df560 100644
--- a/doc/contribute-to-core-lightning/release-checklist.md
+++ b/doc/contribute-to-core-lightning/release-checklist.md
@@ -64,13 +64,13 @@ Here's a checklist for the release process.
    - `git pull`
    - `git tag -a -s v${VERSION} -m v${VERSION}`
    - `git push --tags`
-5. Run `tools/build-release.sh` to:
+5. Run `tools/build-release.sh` (with `--sudo` if you need root to run Docker) to:
    - Create reproducible zipfile
    - Build non-reproducible Fedora image
-   - Build reproducible Ubuntu-v18.04, Ubuntu-v20.04, Ubuntu-v22.04 images. Follow [link](https://docs.corelightning.org/docs/repro#building-using-the-builder-image) for manually Building Ubuntu Images.
+   - Build reproducible Ubuntu-v20.04, Ubuntu-v22.04 and Ubuntu-v24.04 images. Follow [link](https://docs.corelightning.org/docs/repro#building-using-the-builder-image) for manually Building Ubuntu Images.
    - Build Docker images for amd64 and arm64v8. Follow [link](https://docs.corelightning.org/docs/docker-images) for more details on Docker publishing.
    - Create and sign checksums. Follow [link](https://docs.corelightning.org/docs/repro#co-signing-the-release-manifest) for manually signing the release.
-6. The tarballs may be owned by root, so revert ownership if necessary:
+6. If you used `--sudo`, the tarballs may be owned by root, so revert ownership if necessary:
    `sudo chown ${USER}:${USER} *${VERSION}*`
 7. Upload the resulting files to github and save as a draft.
    (<https://github.com/ElementsProject/lightning/releases/>)
diff --git a/tools/build-release.sh b/tools/build-release.sh
index 8c1866e5..673bea70 100755
--- a/tools/build-release.sh
+++ b/tools/build-release.sh
@@ -26,6 +26,7 @@ fi
 FORCE_UNCLEAN=false
 VERIFY_RELEASE=false
 WITHOUT_ZIP=false
+SUDO=
 
 ALL_TARGETS="bin-Fedora bin-Ubuntu docker sign"
 # ALL_TARGETS="bin-Fedora bin-Ubuntu tarball deb docker sign"
@@ -47,6 +48,9 @@ for arg; do
     --without-zip)
         WITHOUT_ZIP=true
         ;;
+    --sudo)
+        SUDO=sudo
+        ;;
     --help)
         echo "Usage: [--force-version=<ver>] [--force-unclean] [--force-mtime=YYYY-MM-DD] [--verify] [TARGETS]"
         echo Known targets: "$ALL_TARGETS"
@@ -201,13 +205,13 @@ if [ -z "${TARGETS##* docker *}" ]; then
     DOCKER_OPTS="$DOCKER_OPTS -t $DOCKER_USER/lightningd:latest"
     DOCKER_OPTS="$DOCKER_OPTS --cache-to=type=local,dest=/tmp/docker-cache --cache-from=type=local,src=/tmp/docker-cache"    
     echo "Docker Options: $DOCKER_OPTS"
-    if sudo docker buildx ls | grep -q 'cln-builder'; then
-        sudo docker buildx use cln-builder
+    if $SUDO docker buildx ls | grep -q 'cln-builder'; then
+        $SUDO docker buildx use cln-builder
     else
-        sudo docker buildx create --name=cln-builder --use
+        $SUDO docker buildx create --name=cln-builder --use
     fi
     # shellcheck disable=SC2086
-    sudo docker buildx build $DOCKER_OPTS .
+    $SUDO docker buildx build $DOCKER_OPTS .
     echo "Pushed multi-platform images tagged as $VERSION and latest"
 fi