Quote password in JoinDomainOrWorkgroup command

Without doing this, you get an error like so:

Missing expression after ','.
At line:1 char:84
+ (Get-WmiObject -Class Win32_ComputerSystem).JoinDomainOrWorkGroup(
'vagrant.local', <<<< Vagrant1,'Administrator@vagr
ant.local')
    + CategoryInfo          : ParserError: (,:String) [],
    ParentContainsErrorRecordException
        + FullyQualifiedErrorId : MissingExpressionAfterToken