Bump ansible-core from 2.11.12 to 2.15.8

Bumps [ansible-core](https://github.com/ansible/ansible) from 2.11.12 to 2.15.8.
- [Release notes](https://github.com/ansible/ansible/releases)
- [Commits](ansible/ansible@v2.11.12...v2.15.8)

---
updated-dependencies:
- dependency-name: ansible-core
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -8,7 +8,7 @@ ansible==4.10.0
     # via
     #   ansible-vault
     #   commcare-cloud (setup.py)
-ansible-core==2.11.12
+ansible-core==2.15.8
     # via ansible
 ansible-inventory==0.6.4
     # via commcare-cloud (setup.py)