Upgrade: bump github.com/prometheus/client_golang from 1.10.0 to 1.11.0

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.10.0 to 1.11.0.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/master/CHANGELOG.md)
- [Commits](prometheus/client_golang@v1.10.0...v1.11.0)

---
updated-dependencies:
- dependency-name: github.com/prometheus/client_golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -2,12 +2,13 @@ module github.com/Luzilla/dnsbl_exporter
 
 go 1.16
 
-require github.com/prometheus/client_golang v1.10.0
+require github.com/prometheus/client_golang v1.11.0
 
 require (
 	github.com/Luzilla/godnsbl v1.0.0
 	github.com/miekg/dns v1.1.42
 	github.com/sirupsen/logrus v1.8.1
+	github.com/smartystreets/goconvey v1.6.4 // indirect
 	github.com/urfave/cli v1.22.5
 	gopkg.in/ini.v1 v1.62.0
 )