Cross-compile for arm64

The .NET 7.0 SDK image for arm64 is broken.

Dockerfile

@@ -1,10 +1,20 @@
-FROM mcr.microsoft.com/dotnet/sdk:7.0 AS publish
-WORKDIR /src
-COPY src/EnergyExporter/EnergyExporter.csproj EnergyExporter/
+# The .NET SDK is broken on arm64, so we have to cross-compile instead.
+FROM mcr.microsoft.com/dotnet/sdk:7.0-bullseye-slim-amd64 AS publish
+
+# Workaround from: https://github.com/dotnet/sdk/issues/28971#issuecomment-1308881150
+ARG TARGETARCH
+ARG TARGETOS
+RUN arch=$TARGETARCH \
+    && if [ "$arch" = "amd64" ]; then arch="x64"; fi \
+    && echo $TARGETOS-$arch > /tmp/rid \
+    && cat /tmp/rid
+
+COPY src/EnergyExporter/EnergyExporter.csproj /src/EnergyExporter/
 WORKDIR /src/EnergyExporter
-RUN dotnet restore EnergyExporter.csproj
+RUN dotnet restore EnergyExporter.csproj -r $(cat /tmp/rid)
+
 COPY src/EnergyExporter/ .
-RUN dotnet publish EnergyExporter.csproj -c Release -o /app/publish
+RUN dotnet publish EnergyExporter.csproj -r $(cat /tmp/rid) -c Release -o /app/publish --no-self-contained --no-restore
 
 FROM  mcr.microsoft.com/dotnet/aspnet:7.0
 WORKDIR /app