Add metrics for current Go process (yorkie-team#262)

go.mod

@@ -10,7 +10,7 @@ require (
 	github.com/grpc-ecosystem/go-grpc-middleware v1.2.2
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/moby/locker v1.0.1
-	github.com/prometheus/client_golang v1.10.0
+	github.com/prometheus/client_golang v1.11.0
 	github.com/rs/xid v1.2.1
 	github.com/spf13/cobra v1.1.3
 	github.com/stretchr/testify v1.7.0
@@ -71,7 +71,7 @@ require (
 	github.com/golangci/misspell v0.3.5 // indirect
 	github.com/golangci/revgrep v0.0.0-20210208091834-cd28932614b5 // indirect
 	github.com/golangci/unconvert v0.0.0-20180507085042-28b1c447d1f4 // indirect
-	github.com/google/go-cmp v0.5.4 // indirect
+	github.com/google/go-cmp v0.5.5 // indirect
 	github.com/gordonklaus/ineffassign v0.0.0-20210225214923-2e10b2664254 // indirect
 	github.com/gostaticanalysis/analysisutil v0.4.1 // indirect
 	github.com/gostaticanalysis/comment v1.4.1 // indirect
@@ -118,7 +118,7 @@ require (
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/polyfloyd/go-errorlint v0.0.0-20210510181950-ab96adb96fea // indirect
 	github.com/prometheus/client_model v0.2.0 // indirect
-	github.com/prometheus/common v0.18.0 // indirect
+	github.com/prometheus/common v0.26.0 // indirect
 	github.com/prometheus/procfs v0.6.0 // indirect
 	github.com/quasilyte/go-ruleguard v0.3.4 // indirect
 	github.com/quasilyte/regex/syntax v0.0.0-20200407221936-30656e2c4a95 // indirect
@@ -159,12 +159,12 @@ require (
 	golang.org/x/mod v0.4.2 // indirect
 	golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4 // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
-	golang.org/x/sys v0.0.0-20210510120138-977fb7262007 // indirect
+	golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40 // indirect
 	golang.org/x/text v0.3.5 // indirect
 	golang.org/x/tools v0.1.3 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	google.golang.org/genproto v0.0.0-20200707001353-8e8330bf89df // indirect
-	google.golang.org/protobuf v1.25.0 // indirect
+	google.golang.org/protobuf v1.26.0-rc.1 // indirect
 	gopkg.in/ini.v1 v1.51.0 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 	honnef.co/go/tools v0.2.0 // indirect