v1.0.0

PeriodicTable v1.0.0

Diff since v0.1.2

Closed issues:

• Why is Element mutable? (#21)
• Mention interactive visualization (#23)
• Consider moving PeriodicTable.jl to JuliaPhysics (#24)
• Deleted by author (#29)

Merged pull requests:

• Dimensionful quantities with Unitful.jl (#19) (@crstnbr)
• Added installation instructions for new pkg mode in README (#20) (@rahulkp220)
• make Element immutable (#22) (@jw3126)
• Readme improvements (#26) (@crstnbr)
• Adds efficient isequal(), isless(), hash() and eachindex() (#28) (@NicholasWMRitchie)
• Install TagBot as a GitHub Action (#30) (@JuliaTagBot)