update go-ucan, with the now spec defined container

https://github.com/ucan-wg/go-ucan/blob/main/pkg/container/SPEC.md

toolkit/client/client_test.go

@@ -36,10 +36,10 @@ func ExampleNewClient() {
 	handleError(err)
 
 	// this container holds the invocation and all the delegation proofs
-	b64, err := cont.ToCborBase64()
+	b64, err := cont.ToBase64StdPadding()
 	handleError(err)
 
-	fmt.Println(string(b64))
+	fmt.Println(b64)
 }
 
 func handleError(err error) {

toolkit/server/exectx/ucanctx_test.go

@@ -64,7 +64,7 @@ func ExampleContext() {
 	cont := container.NewWriter()
 	cont.AddSealed(dlgCid, dlgBytes)
 	cont.AddSealed(invCid, invBytes)
-	contBytes, _ := cont.ToCborBase64()
+	contBytes, _ := cont.ToBase64StdPadding()
 
 	// MAKING A REQUEST: we pass the container in the Bearer HTTP header
 
@@ -84,7 +84,7 @@ func ExampleContext() {
 			// Note: we obviously want something more robust, this is an example
 			// Note: if an error occur, we'll want to return an HTTP 401 Unauthorized
 			data := strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer ")
-			cont, _ := container.FromCborBase64(data)
+			cont, _ := container.FromString(data)
 			ucanCtx, _ := exectx.FromContainer(cont)
 
 			// insert into the go context