Add official support for Postgres 15

[cbaker6]

New Feature / Enhancement Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.

Current Limitation

Postgres 15 is set to release 10/13/22.

Feature / Enhancement Description

It should be added to the CI to test compatibility.

Example Use Case

Developer wants to use Postgres 15 with Parse.

Alternatives / Workarounds

Use older versions of Postgres.

3rd Party References

N/A

[parse-github-assistant]

Thanks for opening this issue!

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[mtrezza]

Great! I've change the PR title, as this would add official support, beyond CI testing.

[parseplatformorg]

🎉 This change has been released in version 5.3.0-alpha.29

[parseplatformorg]

🎉 This change has been released in version 5.4.0-beta.1

[parseplatformorg]

🎉 This change has been released in version 5.4.0-alpha.1

[parseplatformorg]

🎉 This change has been released in version 5.4.0

[parseplatformorg]

🎉 This change has been released in version 5.4.0