Switch r2dbc-postgresql from groupId io.r2dbc to org.postgresql

[breun]

The Spring Boot 2.7 release notes say:

In the Borca release, the group ID of r2dbc-postgresql, the driver for PostgreSQL, has changed from io.r2dbc to org.postgresql. r2dbc-mysql, the driver for MySQL, has been removed. Consider using r2dbc-mariadb as a replacement.

com.google.cloud:spring-cloud-gcp-starter-sql-postgres-r2dbc:3.3.0 depends on io.r2dbc:r2dbc-postgresql:0.8.12.RELEASE. This needs to be changed to org.postgresql:r2dbc-postgresql in a future version to keep up with developments.

[elefeint]

Yep. I am working on it; it's blocking upgrade to Spring Boot 2.7.

[breun]

We noticed that there is also an issue with r2dbc-pool:0.9.0.RELEASE, which is currently provided by Spring Boot 2.7.3 via r2dbc-bom:Borca-SR1, which causes all connections to be evicted immediately. r2dbc-pool:0.9.1.RELEASE fixes this, but that version is not yet managed via an r2dbc-bom release. I don't know if this is a temporary override you would apply via Spring Cloud GCP or if you'll want to wait for a Spring Boot version that fixes this.

[elefeint]

To avoid breaking existing users who are still on Spring Boot 2.6, we won't be changing the version of Postgres R2DBC driver until the next major release of Spring Cloud GCP (that will target Spring Boot 3.0).

You are probably excluding the old driver and including the new one already, but #1185 adds documentation to do so for Spring Boot 2.7 users.
The pool fix is by now released in Spring Boot 2.7.4, so time took care of that.