Add GitHub App "Review Me" to DSC Resource Kit repositories

[johlju]

I suggest we look at adding the GitHub App Review Me to all DSC Resource Kit repositories. It will help by adding the needs review tag when all the status checks are green.
One more step to automate maintainer repetitive tasks.

.github/review-me.yml

# Configuration for probot-review-me - https://github.com/z0al/probot-review-me
when:
  continuous-integration/appveyor/pr: success
  license/cla: success

label: needs review

[johlju]

First out is the repository DscResource.Tests, to test the functionality in real scenarios.

[johlju]

Problems using Review Me (after real scenario tests):

• Does not detect merge conflicts (Support "This branch has conflicts that must be resolved" z0al/probot-review-me#3)
• Does not remove 'waiting...' labels (issue Support optionally removing existing labels when setting z0al/probot-review-me#2)
• Does not support 'waiting for CLA pass' (issue Support more labels with different statuses z0al/probot-review-me#1)
• Updates review label on all PR's on merge of, or push to, any one PR (issue Sets the review label on other event than a push event z0al/probot-review-me#4)

Where the last one is the most serious one for our current workflow. It will set 'needs review' on every PR that has a 'waiting label'. I think we need to look at changing our workflow, or how the labels are used.

[johlju]

Uninstalled Review Me from DscResource.Tests for the time being due to the problems above. I have not remove the configuration file yet, I keep this issue open to see if we can get any improvements to the app, or a reminder to remove the configuration file before closing this issue.