Merge branch 'release-2.0.2' into develop
work around rspec `its` deprecation with rspec-its

Was seeing this deprecation message in the rspec output

    Use of rspec-core's `its` method is deprecated. Use the rspec-its gem
    instead.
updating deprecated rspec methods: be_true, be_false
expose BurstStruct::Burst#keys

expose @hash.keys through BurstStruct::Burst#keys