(maint) Update sync.yaml for new modsync config options
(maint) Update sync.yaml for new modsync config options

Previously the travis.yaml file was unmanaged as it contained customisations not
compatible with modsync.  Now that the required options are available the sync
file can be updated accordingly.  This commit:
- Updates the sudo, dist and before_install commands to install Powershell
- Updates the NOTICE file to indicate the correct dates for the copyright
  holders

puppetlabs/puppetlabs-powershell