Explicitly hint the data source config about the postgresql driver

[IvanBorislavovDimitrov]

Tested with UPS that is created by the binding from another app. UPS example:
{
"dbname":"db-name",
"hostname":"",
"password":"",
"port":"",
"sslcert":"",
"sslrootcert":"",
"uri":"",
"username":""
}

The DB name must be deploy-service databae

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[boyan-velinov]

test comment

[bonzofenix]

hi @IvanBorislavovDimitrov we are deploying to an OSS and it is possible to provide an type to the ups (see https://github.com/cloudfoundry/app-autoscaler-release/pull/2988/files#diff-89bbdc920fb5f6213ef8d874bc13e94f12f19dbb167997e1eea0206bbea41e2bR17)

[IvanBorislavovDimitrov]

hi @bonzofenix,
the username, password and uri are mandatory only

[bonzofenix]

@IvanBorislavovDimitrov yes, provisioning the user-provided-service with -t postgres allows the java oss buildpack to provision the missing Postgres drivers without the changes in this pr, with what is in main.