Upgrade to Go 1.18 and re-vendor dependencies

vendor/google.golang.org/protobuf/internal/filedesc/build.go

@@ -3,11 +3,14 @@
 // license that can be found in the LICENSE file.
 
 // Package filedesc provides functionality for constructing descriptors.
+//
+// The types in this package implement interfaces in the protoreflect package
+// related to protobuf descripriptors.
 package filedesc
 
 import (
 	"google.golang.org/protobuf/encoding/protowire"
-	"google.golang.org/protobuf/internal/fieldnum"
+	"google.golang.org/protobuf/internal/genid"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
 	preg "google.golang.org/protobuf/reflect/protoregistry"
@@ -126,24 +129,24 @@ func (db *Builder) unmarshalCounts(b []byte, isFile bool) {
 			b = b[m:]
 			if isFile {
 				switch num {
-				case fieldnum.FileDescriptorProto_EnumType:
+				case genid.FileDescriptorProto_EnumType_field_number:
 					db.NumEnums++
-				case fieldnum.FileDescriptorProto_MessageType:
+				case genid.FileDescriptorProto_MessageType_field_number:
 					db.unmarshalCounts(v, false)
 					db.NumMessages++
-				case fieldnum.FileDescriptorProto_Extension:
+				case genid.FileDescriptorProto_Extension_field_number:
 					db.NumExtensions++
-				case fieldnum.FileDescriptorProto_Service:
+				case genid.FileDescriptorProto_Service_field_number:
 					db.NumServices++
 				}
 			} else {
 				switch num {
-				case fieldnum.DescriptorProto_EnumType:
+				case genid.DescriptorProto_EnumType_field_number:
 					db.NumEnums++
-				case fieldnum.DescriptorProto_NestedType:
+				case genid.DescriptorProto_NestedType_field_number:
 					db.unmarshalCounts(v, false)
 					db.NumMessages++
-				case fieldnum.DescriptorProto_Extension:
+				case genid.DescriptorProto_Extension_field_number:
 					db.NumExtensions++
 				}
 			}