在Go上安装带有“ go get”的Go软件包是否算作克隆？

When a user installs a Go package with the command:

go get github.com/username/repositoryname/packagename

is this counted in the GitHub traffic as cloning?

I have a new Go repository and my GitHub account counted several clones. However I installed my own package as a test with the go get command a few times. Is this also counted as cloning or only when a user clicks on 'Clone in desktop'?

Yes. go get clones the repository (as well as any submodules in the vendor directory if GO15VENDOREXPERIMENT is enabled.) Since the repository is being cloned, it will count in the traffic as cloning.