Use head_branch metric (#2549)

Co-authored-by: Yusuke Kuoka <ykuoka@gmail.com>

go.mod

@@ -9,8 +9,7 @@ require (
 	github.com/go-logr/logr v1.2.3
 	github.com/golang-jwt/jwt/v4 v4.5.0
 	github.com/google/go-cmp v0.5.9
-	github.com/google/go-github/v47 v47.1.0
-	github.com/google/go-github/v50 v50.0.0
+	github.com/google/go-github/v52 v52.0.0
 	github.com/google/uuid v1.3.0
 	github.com/gorilla/mux v1.8.0
 	github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79
@@ -26,8 +25,8 @@ require (
 	github.com/teambition/rrule-go v1.8.2
 	go.uber.org/multierr v1.7.0
 	go.uber.org/zap v1.24.0
-	golang.org/x/net v0.8.0
-	golang.org/x/oauth2 v0.1.0
+	golang.org/x/net v0.9.0
+	golang.org/x/oauth2 v0.7.0
 	golang.org/x/sync v0.1.0
 	gomodules.xyz/jsonpatch/v2 v2.2.0
 	gopkg.in/yaml.v2 v2.4.0
@@ -39,10 +38,12 @@ require (
 )
 
 require (
+	github.com/ProtonMail/go-crypto v0.0.0-20230217124315-7d5c6f04bbb8 // indirect
 	github.com/aws/aws-sdk-go v1.44.122 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/boombuler/barcode v1.0.1-0.20190219062509-6c824513bacc // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
+	github.com/cloudflare/circl v1.1.0 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.0 // indirect
 	github.com/emicklei/go-restful/v3 v3.9.0 // indirect
 	github.com/evanphx/json-patch/v5 v5.6.0 // indirect
@@ -89,10 +90,10 @@ require (
 	github.com/stretchr/objx v0.5.0 // indirect
 	github.com/urfave/cli v1.22.2 // indirect
 	go.uber.org/atomic v1.7.0 // indirect
-	golang.org/x/crypto v0.1.0 // indirect
-	golang.org/x/sys v0.6.0 // indirect
-	golang.org/x/term v0.6.0 // indirect
-	golang.org/x/text v0.8.0 // indirect
+	golang.org/x/crypto v0.7.0 // indirect
+	golang.org/x/sys v0.7.0 // indirect
+	golang.org/x/term v0.7.0 // indirect
+	golang.org/x/text v0.9.0 // indirect
 	golang.org/x/time v0.3.0 // indirect
 	golang.org/x/tools v0.6.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect