Multiarch Docker Build (#104) (#129)

* Improved Makefile
* Multiarch Docker build (amd64, arm64 and armv7)
* closes #104

cmd/hc/main.go

@@ -0,0 +1,35 @@
+// source taken from https://git.prolicht.digital/golib/healthcheck/-/blob/master/cmd/hc/main.go
+
+package main
+
+import (
+	"net/http"
+	"os"
+	"time"
+)
+
+// main checks the given URL, if the response is not 200, it will return with exit code 1
+// on success, exit code 0 will be returned
+func main() {
+	os.Exit(checkWebEndpointFromArgs())
+}
+
+func checkWebEndpointFromArgs() int {
+	if len(os.Args) < 2 {
+		return 1
+	}
+	if status := checkWebEndpoint(os.Args[1]); !status {
+		return 1
+	}
+	return 0
+}
+
+func checkWebEndpoint(url string) bool {
+	client := &http.Client{
+		Timeout: time.Second * 2,
+	}
+	if resp, err := client.Get(url); err != nil || resp.StatusCode < 200 || resp.StatusCode > 299 {
+		return false
+	}
+	return true
+}