libfork: add version 3.8.0

[toge]

Specify library name and version: libfork/3.8.0

ConorWilliams/libfork@v3.7.2...v3.8.0

---

• 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 ✔️

All green in build 1 (c3a4061d117deb64a45e023fd67f54562ff7a800):

• libfork/3.8.0:
  All packages built successfully! (All logs)

• libfork/3.7.2:
  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 1 (c3a4061d117deb64a45e023fd67f54562ff7a800):

• libfork/3.7.2:
  All packages built successfully! (All logs)

• libfork/3.8.0:
  All packages built successfully! (All logs)

[RubenRBS]

Thanks! I'll submit a PR upstream shortly to improve their Conan 2 instructions, as they seem a bit outdated, we now support this in Conan after all! :)