(MODULES-9432) Remove Style/HashSyntax rubocop rule

[eimlav]

This rule is used to enforce pre Ruby 1.9 hash syntax:

{:a => 2}

Since the module no longer supports Puppet versions which correspond
with anything pre Ruby 1.9, this should be removed to enforce the modern
hash syntax:

{a: 2, b: 1}

[joshcooper]

I don't think we should do this, because puppetserver 5.x uses JRuby 1.7 which is language compatible with MRI 1.9. So installing this module on puppetserver 5/PE 2018.1 will cause compilation to fail. See alsoMODULES-6139 and MODULES-8695

[eimlav]

Hi @joshcooper thanks for the info. For now I'll disable the rule in the affected block in #1031 and we can look at this issue another time. Cheers.