Upgrade to RuboCop 1.86

[haines]

Parallel 2.0 is out, and RuboCop 1.86 relaxes its constraint so that the new version may be installed.

Unfortunately, this results in Standard being downgraded to 1.35.0.1 when attempting to upgrade Parallel.

These are the new cops that need to be configured for Standard to support RuboCop 1.86:

• Lint/DataDefineOverride
• Lint/UnreachablePatternBranch
• Style/FileOpen
• Style/MapJoin
• Style/OneClassPerFile
• Style/PartitionInsteadOfDoubleSelect
• Style/PredicateWithKind
• Style/ReduceToHash
• Style/RedundantMinMaxBy
• Style/RedundantStructKeywordInit
• Style/SelectByKind
• Style/SelectByRange
• Style/TallyMethod

I'd be happy to create a PR but am not sure what the policy is on enabling or disabling newly-introduced cops.