Replace go-kit/kit with go-kit/log

github.com/go-kit/kit is only being used for the log packages and brings
in a lot of dependencies as compared to github.com/go-kit/log. This
would help determine how useful switching would be.

For reference see kubernetes/kubernetes#102144 and prometheus/common#255 (comment)

collector/exporter.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 	"time"
 
-	kitlog "github.com/go-kit/kit/log"
-	"github.com/go-kit/kit/log/level"
+	kitlog "github.com/go-kit/log"
+	"github.com/go-kit/log/level"
 	pgx "github.com/jackc/pgx/v4"
 	"github.com/prometheus/client_golang/prometheus"
 )

go.mod

@@ -4,10 +4,23 @@ go 1.13
 
 require (
 	github.com/alecthomas/units v0.0.0-20201120081800-1786d5ef83d4 // indirect
-	github.com/go-kit/kit v0.12.0
+	github.com/cespare/xxhash/v2 v2.1.2 // indirect
+	github.com/go-kit/log v0.2.0
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/go-cmp v0.5.6 // indirect
 	github.com/jackc/pgx/v4 v4.10.1
+	github.com/kr/text v0.2.0 // indirect
+	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.11.0
 	github.com/prometheus/common v0.32.1
+	github.com/prometheus/procfs v0.7.3 // indirect
+	github.com/stretchr/testify v1.7.0 // indirect
+	golang.org/x/crypto v0.0.0-20210915214749-c084706c2272 // indirect
+	golang.org/x/sys v0.0.0-20210917161153-d61c044b1678 // indirect
+	golang.org/x/text v0.3.7 // indirect
+	google.golang.org/protobuf v1.27.1 // indirect
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
+	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )