fix: multiplatform compatibility (#17)

* Fix multiplatform compatibility

Even though the builder image was pulling multi-arch images the final binary was being built for amd64 arch only.

* chore: keep base image label

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Co-authored-by: Konstantin Chukhlomin <mail@chuhlomin.com>

Dockerfile

@@ -7,7 +7,7 @@ RUN go test -mod=vendor -cover ./...
 RUN go build -mod=vendor -o /go/bin/app
 
 
-FROM gcr.io/distroless/static:966f4bd97f611354c4ad829f1ed298df9386c2ec
+FROM --platform=$BUILDPLATFORM gcr.io/distroless/static:966f4bd97f611354c4ad829f1ed298df9386c2ec
 # latest-amd64 -> 966f4bd97f611354c4ad829f1ed298df9386c2ec
 # https://github.com/GoogleContainerTools/distroless/tree/master/base