Remove rogue newline in readme

[ViddeM]

Make sure that:

• You have read the contribution guidelines.
• You have created a feature request first to discuss your contribution intent. Please reference the feature request ticket number in the pull request.
• You use the code formatters provided here and have them applied to your changes. Don't submit any formatting related changes.
• You submit test cases (unit or integration tests) that back your changes.

Issue description

New Public APIs

Additional context

[ViddeM]

It felt like this change fit under the trivial contributions part of For all but the most trivial of contributions, please [create a ticket](https://github.com/pgjdbc/r2dbc-postgresql/blob/main/.github/CONTRIBUTING.adoc#create-a-ticket).

[mp911de]

Thanks a lot. A pull request is sufficient in this case.