Add SECURITY.md file

[pemtajo]

Following Nubank security guidelines - This PR adds the SECURITY.md file to the repository

[bookworm-app]

Hi. 👋

I'm bookworm and I'll help you merge your change.

You can post a comment on this PR with one of the following commands:

bookworm/release-it

1. Add exactly one of the following labels to this PR: major, minor, patch.

2. Fill the Changelog: section of the PR description.

3. Wait until all the checks have passed and someone has approved the PR.

4. Comment bookworm/release-it on this PR.

I'll take care of updating CHANGELOG.md, bumping project.clj and merging this PR.

Note: a stable version will be generated (that is Bumpito will update to it).

bookworm/release-beta

1. Add exactly one of the following labels to this PR: major, minor, patch.

2. Comment bookworm/release-beta on this PR.

I'll take care of generating a beta version based on these changes and
when it finishes I'll post a comment with the version that was generated.

bookworm/skip-release

This command should be used if you are changing something other than production code or docstrings that engineers can
see in their IDEs (e.g. README, CHANGELOG, tests, etc).

1. Wait until all the checks have passed and someone has approved the PR.

2. Comment bookworm/skip-release on this PR.

I'll take care of merging this PR.

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If you have any problem, please reach my creators at #foundation-tribe