Add lint step to PR pipeline

[leizor]

This PR is based off of #35

[grafanabot]

coverage_report.out

lint.out

[grafanabot]

Go coverage report:

Click to expand.

File	%
github.com/grafana/influx2cortex/pkg/errorx/errors.go	67.3%
github.com/grafana/influx2cortex/pkg/errorx/http_translator.go	100.0%
github.com/grafana/influx2cortex/pkg/influx/api.go	95.0%
github.com/grafana/influx2cortex/pkg/influx/errors.go	100.0%
github.com/grafana/influx2cortex/pkg/influx/parser.go	83.8%
github.com/grafana/influx2cortex/pkg/influx/recorder.go	100.0%
github.com/grafana/influx2cortex/pkg/remotewrite/client.go	69.1%
github.com/grafana/influx2cortex/pkg/remotewrite/measured_client.go	88.9%
github.com/grafana/influx2cortex/pkg/remotewrite/recorder.go	100.0%
github.com/grafana/influx2cortex/pkg/tenant/resolver.go	75.6%
github.com/grafana/influx2cortex/pkg/tenant/tenant.go	91.7%
github.com/grafana/influx2cortex/pkg/util/extract_forwarded.go	66.7%
github.com/grafana/influx2cortex/pkg/util/http.go	68.3%
github.com/grafana/influx2cortex/pkg/util/log/experimental.go	0.0%
github.com/grafana/influx2cortex/pkg/util/log/log.go	0.0%
github.com/grafana/influx2cortex/pkg/util/log/rate_limit.go	90.0%
github.com/grafana/influx2cortex/pkg/util/log/wrappers.go	0.0%
github.com/grafana/influx2cortex/pkg/util/push/push.go	60.0%
total	73.1%

Go lint report:

Click to expand.

pkg/influx/api.go:17:5: `ingesterClientRequestDuration` is unused (deadcode)
var ingesterClientRequestDuration = promauto.NewHistogramVec(prometheus.HistogramOpts{
    ^
pkg/errorx/http_translator.go:27:23: Error return value of `(github.com/go-kit/log.Logger).Log` is not checked (errcheck)
		level.Error(log).Log("msg", "canceled", "response_code", code, "err", err)
		                    ^
pkg/errorx/http_translator.go:32:23: Error return value of `(github.com/go-kit/log.Logger).Log` is not checked (errcheck)
			level.Warn(log).Log("msg", errx.Message(), "response_code", code, "err", tryUnwrap(errx))
			                   ^
pkg/errorx/http_translator.go:34:24: Error return value of `(github.com/go-kit/log.Logger).Log` is not checked (errcheck)
			level.Error(log).Log("msg", errx.Message(), "response_code", code, "err", tryUnwrap(errx))
			                    ^
pkg/util/log/log.go:60:13: Error return value of `logger.Log` is not checked (errcheck)
		logger.Log("err", fmt.Sprintf("%+v", err))
		          ^
cmd/influx2cortex/main.go:9:2: SA1019: package github.com/go-kit/kit/log is deprecated: Use github.com/go-kit/log instead. (staticcheck)
	"github.com/go-kit/kit/log"
	^
cmd/influx2cortex/main.go:10:2: SA1019: package github.com/go-kit/kit/log/level is deprecated: Use github.com/go-kit/log/level instead. (staticcheck)
	"github.com/go-kit/kit/log/level"
	^
pkg/errorx/http_translator.go:8:2: SA1019: package github.com/go-kit/kit/log is deprecated: Use github.com/go-kit/log instead. (staticcheck)
	"github.com/go-kit/kit/log"
	^
pkg/errorx/http_translator.go:9:2: SA1019: package github.com/go-kit/kit/log/level is deprecated: Use github.com/go-kit/log/level instead. (staticcheck)
	"github.com/go-kit/kit/log/level"
	^
pkg/influx/api.go:8:2: SA1019: package github.com/go-kit/kit/log is deprecated: Use github.com/go-kit/log instead. (staticcheck)
	"github.com/go-kit/kit/log"
	^
pkg/influx/api.go:9:2: SA1019: package github.com/go-kit/kit/log/level is deprecated: Use github.com/go-kit/log/level instead. (staticcheck)
	"github.com/go-kit/kit/log/level"
	^

[leizor]

Alright, looking good! Gonna close this and #35 and re-open a combined one.