docs(upgrade): adding acknowledge section

[Anavelyz]

Pull Request description

Adding the acknowledgements section in the readme to mention the grants received from the PSF.

Solve #210

Pull Request checklists

This PR is a:

• [ ] bug-fix
• [ ] new feature
• [x] maintenance

About this PR:

• [ ] it includes tests.
• [ ] the tests are executed on CI.
• [ ] the tests generate log file(s) (path).
• [ ] pre-commit hooks were executed locally.
• [ ] this PR requires a project documentation update.

Author's checklist:

• [ ] I have reviewed the changes and it contains no misspelling.
• [ ] The code is well commented, especially in the parts that contain more complexity.
• [ ] New and old tests passed locally.

[xmnlab]

@Anavelyz there is a new git submodule added here .. probably by mistake, could you remove that please?

[github-actions[bot]]

:tada: This PR is included in version 0.7.2 :tada:

The release is available on:

• 0.7.2
• GitHub release

Your semantic-release bot :package::rocket: