Update changelog for v3.8.2 release
## HEAD (Unreleased)
+## 3.8.2 (October 18, 2021)
+
- [sdk/python] Relax PyYaml dependency to allow upgrade to PyYaml 6.0 (https://github.com/pulumi/pulumi-kubernetes/pull/1768)
- [go/sdk] Add missing types for deprecated Provider (https://github.com/pulumi/pulumi-kubernetes/pull/1771)
