Update changelog for v3.5.0 release
## HEAD (Unreleased)
+## 3.5.0 (June 30, 2021)
+
- Update pulumi dependencies v3.5.1 (https://github.com/pulumi/pulumi-kubernetes/pull/1623)
- Skip cluster connectivity check in yamlRenderMode (https://github.com/pulumi/pulumi-kubernetes/pull/1629)
- Handle different namespaces for server-side diff (https://github.com/pulumi/pulumi-kubernetes/pull/1631)
