Merge pull request #33 from cabify/dependabot/go_modules/github.com/prometheus/client_golang-1.11.1

Bump github.com/prometheus/client_golang from 1.0.0 to 1.11.1

Draft for release candidate v1.1.0

Adding support for labels using unsigned integers in the CHANGELOG

Adding support for unsigned integers

Drafting the v1.0.0

Use golangci-lint as linter (#29)

Use Travis badge from .org instead of .com

Document Histogram&Summary builders tags behavior

Summaries: require objectives to be explicit

Histograms: require buckets to be explicit

Build prometheus.Histogram instead of Observer

Prepare release v0.3.0 for summary changes (#25)

Add objectives to summaries from struct tag

Upgrade golang client to v1.0.0 version