Invalid push requests when tag included

[kalantar]

When an image name includes a tag, for example, of the form:
registry/namespace/repository:tag
an invalid push request is made. Currently, pushUrl is computed (in BuildPushAndDeleteImage()) as:
pushUrl := ("/v1.10/images/" + passedParams.Image_name + "/push")
Per the spec, https://docs.docker.com/reference/api/docker_remote_api_v1.14/#push-an-image-on-the-registry, the tag should be a query parameter. passedParams.Image_name should be parsed to identify whether or not a :tag is include. If so, it should be appended to the URL as "?tag=:tag"

Something like this should work:

    fullImageName := passedParams.Image_name
    registryNamespace := ""
    repository := fullImageName
    tag := ""
    repositoryIdx := strings.LastIndex(fullImageName, "/")
    if repositoryIdx > 0 {
            registryNamespace = fullImageName[:repositoryIdx]
            repository = fullImageName[repositoryIdx:]
            splitStrings := strings.Split(repository, ":")
            repository = splitStrings[0]
            tag = splitStrings[1]
    }
    pushUrl := ("/v1.10/images/" + registryNamespace + repository + "/push")
    if tag != "" {
            pushUrl = (pushUrl + "?tag=" + tag)
    }