Added 'netrc' credentials to documentation

[cpiment]

I was trying to use a control repo cloned by HTTPS instead of SSH, and detected that in the templates existed a r10k.code.viaHttps.credentials setting that was not referenced in the documentation. This PR tries to fix that.

[CLAassistant]

All committers have signed the CLA.

[ldaneliukas]

Thanks for the fix @cpiment! Could you possibly add info on using existingSecret for viaHttps so it matches viaSsh?

[cpiment]

Thanks for your comments @ldaneliukas. I have made the suggested changes to README.md

[Xtigyro]

@cpiment Could you please also bump the bugfix version of the chart in Chart.yaml and update the CHANGELOG.md?

[cpiment]

Hi @Xtigyro, I made the requested changes. Thanks!

[ldaneliukas]

Great! One last thing, the unit test snapshots include the chart version, could you update them with helm unittest . -u. ?

[cpiment]

Hi @ldaneliukas, I have updated the unit test snapshots as requested. Thanks!