Changeset 52618 for trunk

Bundled Themes: Bump the versions for bundled themes for release.

This bumps the versions of the default bundled themes in preparation for release with WordPress 5.9.

The new versions are:

• Twenty Ten: 3.6
• Twenty Eleven: 4.0
• Twenty Twelve: 3.6
• Twenty Thirteen: 3.5
• Twenty Fourteen: 3.3
• Twenty Fifteen: 3.1
• Twenty Sixteen: 2.6
• Twenty Seventeen: 2.9
• Twenty Nineteen: 2.2
• Twenty Twenty: 1.9
• Twenty Twenty-One: 1.5

Props audrasjb.
Fixes #54783.