Add Colombian holidays

[luisprmat]

Contributing a new country ?

• Have you checked to ensure there aren't other open Pull Requests for the same country?

Yes, i have checked and I know PR#55 exists for the same country, but it has problems with phpstan. I have rewritten the function that generated problems with types and now the phpstan analysis passes.

PR#55 can be closed in favour of this.

1. Create a new class in the Countries directory. It should extend the Country class.
2. Add a test for the new country in the tests directory.
3. Run the tests so a snapshot gets created.
4. Verify the result in the newly created snapshot is correct.

[Nielsvanpach]

Could you help #55 with fixing it instead? Thanks!