chore: Only check the bootstrap daemon checksum on release.

It's pure toil until then. It's only interesting as part of the release
checklist, not in regular PRs.

.github/scripts/tox-bootstrapd-docker

@@ -3,10 +3,11 @@
 set -exu -o pipefail
 
 LOCAL="${1:-}"
+CHECK="${2:-}"
 
 readarray -t FILES <<<"$(git ls-files)"
 
-if ! tar c "${FILES[@]}" | docker build -f other/bootstrap_daemon/docker/Dockerfile -t toxchat/bootstrap-node - 2>&1 | tee docker-build.log; then
+if ! tar c "${FILES[@]}" | docker build --build-arg="CHECK=$CHECK" -f other/bootstrap_daemon/docker/Dockerfile -t toxchat/bootstrap-node - 2>&1 | tee docker-build.log; then
   grep -o "::error.*::[a-f0-9]*  /usr/local/bin/tox-bootstrapd" docker-build.log
   false
 fi

.github/workflows/docker.yml

@@ -25,7 +25,9 @@ jobs:
         with:
           submodules: recursive
       - name: Docker Build
-        run: .github/scripts/tox-bootstrapd-docker local
+        run: .github/scripts/tox-bootstrapd-docker local "$CHECK"
+        env:
+          CHECK: "${{ contains(github.event.pull_request.title, 'chore: Release ') && 'sha256sum' || 'echo' }}"
       - name: Push latest image to DockerHub
         if: ${{ github.event_name == 'push' }}
         run: docker push toxchat/bootstrap-node:latest

other/bootstrap_daemon/docker/Dockerfile

@@ -48,8 +48,9 @@ RUN CC=clang cmake -B_build -H. \
 # Verify checksum from dev-built binary, so we can be sure Docker Hub doesn't
 # mess with your binaries.
 COPY other/bootstrap_daemon/docker/tox-bootstrapd.sha256 other/bootstrap_daemon/docker/
-RUN SHA256="$(sha256sum /usr/local/bin/tox-bootstrapd)" && \
-    (sha256sum -c other/bootstrap_daemon/docker/tox-bootstrapd.sha256 || \
+ARG CHECK=sha256sum
+RUN SHA256="$("$CHECK" /usr/local/bin/tox-bootstrapd)" && \
+    ("$CHECK" -c other/bootstrap_daemon/docker/tox-bootstrapd.sha256 || \
     (echo "::error file=other/bootstrap_daemon/docker/tox-bootstrapd.sha256,line=1::$SHA256" && \
      false))