Drop deprecated github.com/golang/protobuf

Signed-off-by: Hidde Beydals <hello@hidde.co>

go.mod

@@ -28,7 +28,6 @@ require (
 	github.com/fluxcd/pkg/testserver v0.2.0
 	github.com/fluxcd/pkg/untar v0.1.0
 	github.com/fluxcd/source-controller/api v0.24.4
-	github.com/golang/protobuf v1.5.2
 	github.com/hashicorp/go-retryablehttp v0.7.1
 	github.com/hashicorp/vault/api v1.5.0
 	github.com/onsi/gomega v1.19.0
@@ -39,6 +38,7 @@ require (
 	google.golang.org/api v0.81.0
 	google.golang.org/genproto v0.0.0-20220525015930-6ca3db687a9d
 	google.golang.org/grpc v1.46.2
+	google.golang.org/protobuf v1.28.0
 	k8s.io/api v0.24.0
 	k8s.io/apiextensions-apiserver v0.24.0
 	k8s.io/apimachinery v0.24.0
@@ -121,6 +121,7 @@ require (
 	github.com/golang-jwt/jwt v3.2.1+incompatible // indirect
 	github.com/golang-jwt/jwt/v4 v4.3.0 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/btree v1.0.1 // indirect
 	github.com/google/gnostic v0.5.7-v3refs // indirect
@@ -204,7 +205,6 @@ require (
 	golang.org/x/time v0.0.0-20220224211638-0e9765cccd65 // indirect
 	gomodules.xyz/jsonpatch/v2 v2.2.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
-	google.golang.org/protobuf v1.28.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.66.4 // indirect
 	gopkg.in/square/go-jose.v2 v2.6.0 // indirect