docs: Add security policy file

[validcube]

This is taken from https://github.com/ReVanced/revanced-manager/blob/dev/SECURITY.md

[oSumAtrIX]

Some references to ReVanced Manager have to be changed to ReVanced API

[alexandreteles]

Technically the only supported version is whatever is in production (main) and Dev works as staging grounds for changes before moving those into production. Might want to change that before merging.

[validcube]

Technically the only supported version is whatever is in production (main) and Dev works as staging grounds for changes before moving those into production. Might want to change that before merging.

I think development branch should be included, because it allows people to flag a security vulnerability during development which helps us fix a security hole before merging to production.

[alexandreteles]

Technically the only supported version is whatever is in production (main) and Dev works as staging grounds for changes before moving those into production. Might want to change that before merging.

I think development branch should be included, because it allows people to flag a security vulnerability during development which helps us fix a security hole before merging to production.

We can integrate it, but I'm not providing security updates to development versions :)