(PUP-3126) upgrade win32-service to 0.8.6 - 2.0.0-x64

This upgrades the win32-service gem to at least 0.8.6 to take advantage of the
fixes to the service gem. The changes have been verified to only contain the
fixes that we have provided in PUP-1283, PUP-2987, and PUP-3008.