libgphoto2: use version range for libxml2

[mayeut]

Specify library name and version: libgphoto2/all

libxml2<2.12.5 has known security issues. We can now use version range: c.f. #23277

---

• 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.

[conan-center-bot]

Conan v1 pipeline ✔️

Warning

Conan Center will stop receiving updates for Conan 1.x packages soon - please see announcement.

All green in build 4 (923863cd13c5137d77468578588218b53e70450d):

• libgphoto2/2.5.27:
  Built 8 packages out of 11 (All logs)

• libgphoto2/2.5.31:
  Built 8 packages out of 11 (All logs)

---

Conan v2 pipeline ✔️

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

All green in build 4 (923863cd13c5137d77468578588218b53e70450d):

• libgphoto2/2.5.31:
  Built 6 packages out of 10 (All logs)

• libgphoto2/2.5.27:
  Built 6 packages out of 10 (All logs)