chore: require go 1.22/1.23, upgrade protobuf, upgrade all deps

Go upgrade:
- Go 1.23 is current => use that for release builds
- Go 1.22 is less than one year old, it's desirable to support it.
- The [`Go Toolchains`](https://go.dev/doc/toolchain) stuff is available
  in both of these (would also be in Go 1.21). That is quite nice stuff,
  but required some changes to how we versions we use in CircleCI and
  the `release-docker` Makefile target.

Protobuf upgrade:
- Go to protobuf GH release website
- Download latest locally
- run `sha256sum`
- replace existing pinned hashes
- `make generate`

Deps upgrade:
- `go get -t -u all`
- repository moves aren't handled well automatically, fix manually
- repeat until no changes

rpc/grpcclientidentity/example/pdu/grpcauth_grpc.pb.go

@@ -1,4 +1,8 @@
 // Code generated by protoc-gen-go-grpc. DO NOT EDIT.
+// versions:
+// - protoc-gen-go-grpc v1.5.1
+// - protoc             v5.28.0
+// source: grpcauth.proto
 
 package pdu
 
@@ -11,8 +15,12 @@ import (
 
 // This is a compile-time assertion to ensure that this generated file
 // is compatible with the grpc package it is being compiled against.
-// Requires gRPC-Go v1.32.0 or later.
-const _ = grpc.SupportPackageIsVersion7
+// Requires gRPC-Go v1.64.0 or later.
+const _ = grpc.SupportPackageIsVersion9
+
+const (
+	Greeter_Greet_FullMethodName = "/pdu.Greeter/Greet"
+)
 
 // GreeterClient is the client API for Greeter service.
 //
@@ -30,8 +38,9 @@ func NewGreeterClient(cc grpc.ClientConnInterface) GreeterClient {
 }
 
 func (c *greeterClient) Greet(ctx context.Context, in *GreetRequest, opts ...grpc.CallOption) (*GreetResponse, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
 	out := new(GreetResponse)
-	err := c.cc.Invoke(ctx, "/pdu.Greeter/Greet", in, out, opts...)
+	err := c.cc.Invoke(ctx, Greeter_Greet_FullMethodName, in, out, cOpts...)
 	if err != nil {
 		return nil, err
 	}
@@ -40,20 +49,24 @@ func (c *greeterClient) Greet(ctx context.Context, in *GreetRequest, opts ...grp
 
 // GreeterServer is the server API for Greeter service.
 // All implementations must embed UnimplementedGreeterServer
-// for forward compatibility
+// for forward compatibility.
 type GreeterServer interface {
 	Greet(context.Context, *GreetRequest) (*GreetResponse, error)
 	mustEmbedUnimplementedGreeterServer()
 }
 
-// UnimplementedGreeterServer must be embedded to have forward compatible implementations.
-type UnimplementedGreeterServer struct {
-}
+// UnimplementedGreeterServer must be embedded to have
+// forward compatible implementations.
+//
+// NOTE: this should be embedded by value instead of pointer to avoid a nil
+// pointer dereference when methods are called.
+type UnimplementedGreeterServer struct{}
 
 func (UnimplementedGreeterServer) Greet(context.Context, *GreetRequest) (*GreetResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method Greet not implemented")
 }
 func (UnimplementedGreeterServer) mustEmbedUnimplementedGreeterServer() {}
+func (UnimplementedGreeterServer) testEmbeddedByValue()                 {}
 
 // UnsafeGreeterServer may be embedded to opt out of forward compatibility for this service.
 // Use of this interface is not recommended, as added methods to GreeterServer will
@@ -63,6 +76,13 @@ type UnsafeGreeterServer interface {
 }
 
 func RegisterGreeterServer(s grpc.ServiceRegistrar, srv GreeterServer) {
+	// If the following call pancis, it indicates UnimplementedGreeterServer was
+	// embedded by pointer and is nil.  This will cause panics if an
+	// unimplemented method is ever invoked, so we test this at initialization
+	// time to prevent it from happening at runtime later due to I/O.
+	if t, ok := srv.(interface{ testEmbeddedByValue() }); ok {
+		t.testEmbeddedByValue()
+	}
 	s.RegisterService(&Greeter_ServiceDesc, srv)
 }
 
@@ -76,7 +96,7 @@ func _Greeter_Greet_Handler(srv interface{}, ctx context.Context, dec func(inter
 	}
 	info := &grpc.UnaryServerInfo{
 		Server:     srv,
-		FullMethod: "/pdu.Greeter/Greet",
+		FullMethod: Greeter_Greet_FullMethodName,
 	}
 	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
 		return srv.(GreeterServer).Greet(ctx, req.(*GreetRequest))