Add LibAFL-Targets Crate as a Dependency

We need to utilize data structures from libafl_targets to interpret the coverage information being gathered by the instrumentation. To do that, we'll depend on the crate the same way we did in our target.

We can add libafl_targets with the sancov_8bit and observers feature to our crate by adding this line to our Cargo.toml file under the [dependencies] section:

libafl_targets = { version = "0.11.2", features = [
    "sancov_8bit",
    "observers",
] }