Bump minimum version of Ansible to 2.7 or greater

[cognifloyd]

Ansible 2.5 is EOL as of yesterday (2019-05-16) because 🎉 Ansible 2.8 2.9 is here.
2.8: https://groups.google.com/forum/#!topic/ansible-announce/OmkhL4zN1oo
2.9: https://groups.google.com/forum/#!topic/ansible-announce/chcjYohq6dA

I have not reviewed the ansible-st2 playbooks to see what we can do if we bump the version to 2.6.

2.6 has lots of bugfixes for include* and import*.
2.7 makes using vars with include* and import* more consistent.
2.8 adds support for content collections (repos like this one with more than one role). better jinja defaults if intermediate dict doesn't exist.
2.9 changes loop+var safety handling. ansible-galaxy collections support improvements

Current ansible support matrix for 2.2 and above:

Ansible Release	Latest Version	Status
devel	2.10 (unreleased, trunk)	In development
2.9	2.9.2 (2019-12-04)	Supported (security and general bug fixes)
2.8	2.8.7 (2019-11-13)	Supported (security and critical bug fixes)
2.7	2.7.15 (2019-11-13)	Supported (security fixes)
2.6	2.6.20 (2019-10-17)	Unsupported (end of life)
2.5	2.5.15 (2019-02-21)	Unsupported (end of life)
2.4	2.4.6 (2018-07-05)	Unsupported (end of life)
2.3	2.3.3 (2017-12-20)	Unsupported (end of life)
2.2	2.2.3 (2017-05-09)	Unsupported (end of life)

2.9 is out so 2.6 is EOL.

[arm4b]

Thanks @cognifloyd for the notice and putting it all together!

We'll definitely need to do/plan migration to the next major Ansible version.

[cognifloyd]

Chart updated. 2.9 is out. 2.6 is EOL.

[setswei]

I would be happy to help with this. I am starting to implement stackstorm for my current employer and I am using Ansible to manage everything. i would be happy to assist with getting these roles up to the latest version

[arm4b]

@setswei Awesome! Pull Requests are welcome!

[setswei]

I will start working on this and get back to you guys soon.

[amanda11]

I don't think there will be much needed, except to update what the min version required is.
I've been using Ansible 2.9 for ages with the playbooks.
Also the CI actions look to be using Ansible 2.9, so should just be a simple change on changing the min version required.