Add tests/config.yml to tell recent versions of ansible-test we don't…

… support Python<3.6 (ansible-collections#517)

Add tests/config.yml to tell recent versions of ansible-test we don't support Python<3.6

SUMMARY
(Ansible 2.12) ansible-test now has a config file that lets us limit tests to those relevant to Python>=3.6
Add this to simplify things.
Unfortunately this hasn't been (and likely won't be) backported to older versions of Ansible, so there's a little while before we can drop the python 2.x compatability code, but this gets us started.
ISSUE TYPE

Feature Pull Request

COMPONENT NAME
tests/sanity
ADDITIONAL INFORMATION

Reviewed-by: Alina Buzachis <None>
Reviewed-by: None <None>

tests/config.yml

@@ -0,0 +1,2 @@
+modules:
+    python_requires: '>=3.6'