web: behavior: Use go-multierror for combining strategy.Pick errors
web: behavior: Use go-multierror for combining strategy.Pick errors

Signed-off-by: David Symons <aa743a0aaec8f7d7a1f01442503957f4d7a2d634@symons.io>

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse