Merge pull request #5979 from sbueringer/pr-book-tgik-cc

🌱 book: add TGIK ClusterClass video

Author: k8s-ci-robot

docs/book/src/developer/guide.md

@@ -229,6 +229,7 @@ CAPI components and architecture
 * [Cluster API Deep Dive - Dec 2020 v1alpha3](https://youtu.be/npFO5Fixqcc)
 * [Cluster API Deep Dive - Sept 2020 v1alpha3](https://youtu.be/9SfuQQeeK6Q)
 * [Declarative Kubernetes Clusters with Cluster API - Oct 2020 v1alpha3](https://youtu.be/i6OWn2zRsZg)
+* [TGI Kubernetes 178: ClusterAPI - ClusterClass & Managed Topologies - Dec 2020 v1beta1](https://www.youtube.com/watch?v=U9CDND0nzRI&list=PL7bmigfV0EqQzxcNpmcdTJ9eFRPBe-iZa&index=5)
 
 Code walkthrough