Upgrade Hugo to 0.163.2

[chalin]

• Contributes to Upgrade to Hugo from v0.157.0 to v0.163.2 #2581
• Upgrades the project's Hugo build from 0.163.1 to 0.163.2:
  • Updates root config.hugo_version and docsy.dev hugo-extended pins.
  • Keeps the theme's minimum supported Hugo version at 0.158.0, since no new syntax or features are adopted.
• Updates the changelog entry and refreshes the refcache (caches the new v0.163.2 release link).
• Verifies the bump with a full, green npm run ci:test: the build logs no Hugo deprecation notices, and the only generated-file change is the cached refcache entry.
• Notes that 0.163.2 is a patch over 0.163.1 with two upstream changes, neither of which affects behavior the theme exercises:
  • Fixes a PostCSS ERR_ACCESS_DENIED regression from the 0.161 Node-permission model.
  • Standardizes Hugo's behavior when external markup converters (e.g. Pandoc, rst) are missing.

$ (cd public && git diff -bw --ignore-blank-lines -I 'Hugo 0.16|buildDate|0\.163\.' -- ':(exclude)*.xml') | grep ^diff
diff --git a/fr/project/about/changelog/index.html b/fr/project/about/changelog/index.html
diff --git a/project/about/changelog/index.html b/project/about/changelog/index.html
diff --git a/refcache.json b/refcache.json