Stage and push helm index where gitconfig is set

[rooftopcellist]

SUMMARY

Fixes: #1246
Related stop-gap fix: #1250

The git config was not being set in the nested gh-pages clone of the awx-operator repo. So when the git push command was run, if failed in the last 1.2.0 release.

This was the error when pushing the index.yaml:

"stderr_lines": ["Author identity unknown", "", "*** Please tell me who you are.", "", "Run", "", "  git config --global user.email \"you@example.com\"", "  git config --global user.name \"Your Name\"", "", "to set your account's default identity.", "Omit --global to set the identity only in this repository.", "", "fatal: empty ident name (for <runner@fv-az575-24.4axca1wo35oulg5iw0gfp2lodh.dx.internal.cloudapp.net>) not allowed"

This also moves the git steps to the helm-release.yml playbook rather than the Makefile.

ISSUE TYPE

• Bug, Docs Fix or other nominal change