manifest: BER encode the OID

[alistair23]

This patch converts the measurement OID to be BER encoded.

I used the following diff to generate the DER encoded data

diff --git a/src/main.rs b/src/main.rs
index 181ca0f..077ecc3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,6 +8,8 @@
 //! (which is generated from here) or the README
 //!

+use asn1_rs::oid;
+use asn1_rs::ToDer;
 use async_std::task;
 use clap::{Parser, Subcommand};
 use futures::future::join_all;
@@ -629,6 +631,10 @@ fn init_logger() {
 #[async_std::main]
 async fn main() -> Result<(), ()> {
     init_logger();
+
+    let oid = oid!(1.3.6.1.4.1.5127);
+    panic!("OID: {:x?}", oid.to_der_vec());
+
     let cli = Args::parse();

     let cntx_ptr = spdm::initialise_spdm_context();

As DER is a subset of BER we can use the DER output directly.