Pin AFLplusplus ref to final Apache2 version

[domenukk]

Description

This makes sure ppl can use LibAFL and all features now and in the future, without accidental licensing issues

Checklist

• I have run ./scripts/precommit.sh and addressed all comments

[rchildre3]

This looks like it also addresses multiple clippy issues currently blocking CI on main. Can we also address the following error:

https://github.com/AFLplusplus/LibAFL/actions/runs/28022336332/job/82941485159#step:5:3047

RUSTDOCFLAGS="--cfg docsrs" cargo +nightly test --doc --workspace --all-features --exclude libafl_qemu --exclude libafl_qemu_sys --exclude libafl_qemu_build --exclude libafl_qemu_runner --exclude libvharness_sys --exclude libafl_sugar --exclude libafl_libfuzzer

error: unused import: `fuzzer::*`
  --> crates/libafl/src/lib.rs:88:59
   |
88 |         corpus::*, events::*, executors::*, feedbacks::*, fuzzer::*, generators::*, inputs::*,
   |                                                           ^^^^^^^^^
   |
   = note: `-D unused-imports` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(unused_imports)]`

Is the proper fix just adding an #[allow(unused_imports)] to the prelude block?

[domenukk]

Will debug the remaining issues in follow up PRs