Build on golang 1.17.x

[pgporada]

I ran the following:

$ go mod init
$ go mod download github.com/beorn7/perks
$ go get github.com/maxctrl_exporter
$ sudo docker build -f Dockerfile .
$ $ sudo docker run -P c828
2021/09/23 21:48:00 Starting MaxScale exporter
2021/09/23 21:48:00 Scraping MaxScale JSON API at: 127.0.0.1:8989
2021/09/23 21:48:00 Started MaxScale exporter, listening on port: 8080

$ curl -s 172.17.0.2:8080/metrics | grep '^go_info'
go_info{version="go1.17.1"} 1
$ curl -s 172.17.0.2:8080/metrics | grep '^maxctrl_exporter_total_scrapes'
maxctrl_exporter_total_scrapes 1

[ktugan]

Looks good to me. Thank you, you are a champ!