Bump pymdown-extensions from 10.21.3 to v11

[dghubble-renovate]

This PR contains the following updates:

Package	Update	Change
pymdown-extensions	major	==10.21.3 → ==11.0

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Release Notes

facelessuser/pymdown-extensions (pymdown-extensions)

v11.0

Compare Source

11.0

• BREAK: B64: Restricts relative links to base_path by default. Can be disabled by setting new restrict_path
  option to False. The new root_path can be specified if paths are desired to be restricted to a different
  location separate base_path which is also used as a relative base for image paths.
• NEW: Drop Python 3.9 support.
• FIX: Tabbed: Fix issue where an empty title would cause an exception.

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