chore(main): release 3.15.0

[github-actions[bot]]

:robot: I have created a release beep boop

3.15.0 (2023-10-09)

Features

• New Action block for layouts enables in-layout buttons (982a690)
• New IT encounter buttons for 5e layout (b57f315)

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[valentine195]

close #288

[github-actions[bot]]

:robot: Release is at https://github.com/javalent/fantasy-statblocks/releases/tag/3.15.0 :sunflower: