Do crossbuild (#18)

Author: bleggett

.github/workflows/release-image.yaml

@@ -65,7 +65,7 @@ jobs:
         with:
           context: .
           file: ./Containerfile
-          platforms: "linux/amd64"
+          platforms: "linux/amd64,linux/arm64"
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           cache-from: type=gha

.release-plz.toml

@@ -1,4 +1,5 @@
-FROM rust:1.91-bookworm@sha256:7ccbffbca64e04b1c19647e236b2a41c54eb4ee58891faa43ed70379f264db40 AS build
+# This is *not* sha-locked as ghcr doesn't have arch-agnostic SHAs ATM, AFAICT.
+FROM rust:1.91-bookworm AS build
 
 RUN apt-get update && apt-get --assume-yes install protobuf-compiler git clang cmake build-essential llvm-dev libclang-dev jq