set default shell to powershell in windows

[thboop]

Chose to not do this via a feature flag as we are rolling out right after another runner so the set of changes should be minimal

https://github.com/github/pe-actions-runtime/issues/84

BREAKING CHANGE we wish to roll this out on 10/23 after ChrisPat has given sufficient notice to customers

[ericsciple]

@bryanmacfarlane @chrispat do we need a feature flag so we can quickly mitigate specific accounts? or is the mitigation to tell customers to add shell: cmd?

[ericsciple]

make sure we get the desired behavior where $LASTEXITCODE bubbles failure

[thboop]

@bryanmacfarlane @chrispat do we need a feature flag so we can quickly mitigate specific accounts? or is the mitigation to tell customers to add shell: cmd?

I spoke to Bryan about this and we don't think this is needed because we are doing this as an independent runner release so we can roll back if needed. We don't really envision toggling this feature flag as once it sits in production for a bit toggling the flag would break users dependent on the functionality.

[chrispat]

I agree that we don't really want to toggle this one.

[dakale]

LGTM

[thboop]

make sure we get the desired behavior where $LASTEXITCODE bubbles failure

This correctly fails builds when run: exit 1 is invoked. the code does go down the correct path as well to set this behavior