docs: Add upgrading guide for TLS metrics (#7051)

Signed-off-by: Simon Behar <simbeh7@gmail.com>

docs/upgrading.md

@@ -6,7 +6,11 @@ the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/#summar
 
 ## Upgrading to v3.3
 
-## feat(server)!: Sync dispatch of webhook events by default
+### [TODO: add commit once PR is merged] feat: Add TLS to Metrics and Telemetry servers (#7041)
+
+This PR adds the ability to send metrics over TLS with a self-signed certificate. In v3.5 this will be enabled by default, so it is recommended that users enable this functionality now.
+
+### [0758eab11](https://github.com/argoproj/argo-workflows/commit/0758eab11decb8a1e741abef3e0ec08c48a69ab8) feat(server)!: Sync dispatch of webhook events by default
 
 This is not expected to impact users.
 
@@ -17,7 +21,7 @@ too long for your client and you may prefer to revert this behaviour.
 To revert this behaviour, restart Argo Server with `ARGO_EVENT_ASYNC_DISPATCH=true`. Make sure that `asyncDispatch=true`
 is logged.
 
-### [bd49c630328d30206a5c5b78cbc9a00700a28e7d](https://github.com/argoproj/argo-workflows/commit/bd49c630328d30206a5c5b78cbc9a00700a28e7d) fix(artifact)!: default https to any URL missing a scheme. Fixes #6973
+### [bd49c6303](https://github.com/argoproj/argo-workflows/commit/bd49c630328d30206a5c5b78cbc9a00700a28e7d) fix(artifact)!: default https to any URL missing a scheme. Fixes #6973
 
 HTTPArtifact without a scheme will now defaults to https instead of http