Remove deprecated 'linenumber' from puppet-lint format
The key 'linenumber' has been deprecated from the puppet-lint format since version 1.0.0 and replaced by 'line': https://github.com/rodjek/puppet-lint/releases/tag/1.0.0
The support for this deprecated key has now been removed: https://github.com/rodjek/puppet-lint/pull/540