Add requirements.txt file for Python dependencies (backport #40)

[mergify]

Description

This PR adds a new requirements.txt file to make it easier to manage the versions of each package in multiple branches.

@Mergifyio backport kilted rolling jazzy

Contributor Checklist

• Current behavior is correctly described in the README documentation.
• Applicable backports have been included in the description.

Reviewer Checklist

• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Applicable backports have been requested

---

This is an automatic backport of pull request #40 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 0ca6886 has failed:

On branch mergify/bp/jazzy/pr-40
Your branch is up to date with 'origin/jazzy'.

You are currently cherry-picking commit 0ca6886.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .github/actions/install_python_packages/action.yml
	new file:   requirements.txt

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   .github/workflows/reusable-ci.yml
	both modified:   README.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally