Add Wietse's Cloud Run book (#6381)

* Update free-programming-books-subjects.md

Add SWE at Google

* Update free-programming-books-subjects.md

Sort local list

* Add Ŵietse' Cloud Run Book

Add Building Serverless Applications on Google Cloud Run by Wietse Venema
- book is sponsored and distributed for free by CockroachDB

books/free-programming-books-subjects.md

@@ -154,6 +154,7 @@ Books that cover a specific programming language can be found in the  [BY PROGRA
 * [AWS Well-Architected Framework](https://docs.aws.amazon.com/wellarchitected/latest/framework) (PDF, HTML)
 * [Azure for Architects, Third Edition](https://azure.microsoft.com/en-us/resources/azure-for-architects/) (PDF) *(email address or account required)*
 * [Azure Functions Succinctly, Syncfusion](https://www.syncfusion.com/ebooks/azure-functions-succinctly) (PDF, Kindle) (email address requested, not required)
+* [Building Serverless Applications with Google Cloud Run](https://www.cockroachlabs.com/guides/oreilly-building-serverless-applications-with-google-cloud-run/) - Wietse Venema (PDF) (email address requested, not required)
 * [Cloud Computing for Science and Engineering](https://cloud4scieng.org/chapters/) - Ian Foster, Dennis B. Gannon (:construction: *in process*)
 * [Cloud Design Patterns](https://docs.microsoft.com/en-us/azure/architecture/patterns/)
 * [Designing Distributed Systems](https://azure.microsoft.com/en-us/resources/designing-distributed-systems/) *(account required)*