avahi: security, bump expat

[mayeut]

Specify library name and version: avahi/all

fix use of vulnerable version of expat, versions<2.6.2 have known vulnerabilites: #23277

Blocked by #23512

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• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[github-actions]

🤖 Beep Boop! This pull request is making changes to 'recipes/avahi//'.

👋 @jwillikers you might be interested. 😉

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 4 (6fbc526b41555d5e6b428797969a12e062d424a9):

• avahi/0.8:
  All packages built successfully! (All logs)

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Conan v2 pipeline ✔️

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

All green in build 4 (6fbc526b41555d5e6b428797969a12e062d424a9):

• avahi/0.8:
  All packages built successfully! (All logs)

[conan-center-bot]

This PR has been automatically merged due to Bump version or Bump dependencies label.
Read https://github.com/conan-io/conan-center-index/blob/master/docs/labels.md#bump-version to obtain more information.