Build and push docker image with many platforms

Signed-off-by: roman-kiselenko <roman.kiselenko.dev@gmail.com>

Author: roman-kiselenko

Dockerfile

@@ -10,7 +10,7 @@ ADD . ./
 
 RUN GOOS=$TARGETOS GOARCH=$TARGETARCH go build -v -o /build/smolgit
 
-FROM alpine/git:2.45.2 AS runner
+FROM --platform=$BUILDPLATFORM alpine/git:2.45.2 AS runner
 
 COPY --from=builder /build/smolgit /usr/bin/smolgit