chore(docker): support multiple platform

fix https://github.com/appleboy/gorush/issues/720

docker/Dockerfile

@@ -0,0 +1,20 @@
+FROM alpine:3.17
+
+ARG TARGETOS
+ARG TARGETARCH
+
+LABEL maintainer="Bo-Yi Wu <appleboy.tw@gmail.com>" \
+  org.label-schema.name="Gorush" \
+  org.label-schema.vendor="Bo-Yi Wu" \
+  org.label-schema.schema-version="1.0"
+
+RUN apk add --no-cache ca-certificates mailcap && \
+  rm -rf /var/cache/apk/*
+
+COPY release/${TARGETOS}/${TARGETARCH}/gorush /bin/
+
+EXPOSE 8088 9000
+HEALTHCHECK --start-period=1s --interval=10s --timeout=5s \
+  CMD ["/bin/gorush", "--ping"]
+
+ENTRYPOINT ["/bin/gorush"]