apply 'go mod tidy'

ci/sync_envoy.sh

@@ -72,5 +72,6 @@ commit_changes () {
 
 
 build_protos
+go mod tidy
 sync_protos
 commit_changes

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/census-instrumentation/opencensus-proto v0.4.1
 	github.com/cncf/xds/go v0.0.0-20231128003011-0fa0005c9caa
 	github.com/envoyproxy/protoc-gen-validate v1.0.4
+	github.com/golang/protobuf v1.5.4
 	github.com/google/go-cmp v0.6.0
 	github.com/planetscale/vtprotobuf v0.5.1-0.20231212170721-e7d721933795
 	github.com/prometheus/client_model v0.6.0
@@ -19,7 +20,6 @@ require (
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/net v0.20.0 // indirect