v0.15.2-develop.0

🐛 Bug Fix

• Add @mdx-js/react to peerDeps for gatsby-plugin-theme-ui #2331 (@hasparus)
• Fix MDXProvider example #2329 (@shawnbot)

Authors: 2

• Piotr Monwid-Olechnowicz (@hasparus)
• Shawn Allen (@shawnbot)