Add profile for GCP CloudSql Postgres driver (hapifhir#676)

* Add profile for GCP CloudSql Postgres driver

* Update pom.xml: comment on cloudsql-postgres profile needs boot profile

* Add link to GCP docs

pom.xml

@@ -676,5 +676,18 @@
  </plugins>
  </build>
  </profile>
+ <!-- For connecting to GCP CloudSQL Postgres instances:
+ https://github.com/GoogleCloudPlatform/cloud-sql-jdbc-socket-factory/blob/main/docs/jdbc.md#postgres-1
+ Needs 'boot' profile as well. -->
+ <profile>
+ <id>cloudsql-postgres</id>
+ <dependencies>
+ <dependency>
+ <groupId>com.google.cloud.sql</groupId>
+ <artifactId>postgres-socket-factory</artifactId>
+ <version>1.17.0</version>
+ </dependency>
+ </dependencies>
+ </profile> 
  </profiles>
 </project>