Add the correct posgresql version 11.15

[Jobsby]

The postgresql version 11.15 blob was a copy of 11.10. This pull-request contains the proper one.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/182323710

The labels on this github issue will be updated when the story is started.

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: Jobsby / name: kyrian (e225d150c399cec13d1f5af4bbdc4594f69e74e2)