Pin libbpfgo version

[maxgio92]

Because libbpf is statically linked I think it would be beneficial for compatibility to pin the libbpfgo version.
Same applies for libbpfgo headers.

For instance, you could keep libbpfgo as submodule and bump it and test it as soon as a new release or even commit only is available.

[alegrey91]

I agree with you, we should pin the libbpf version in order to make harpoon more stable.

[maxgio92]

IMO it is be as simple as adding it as submodule maxgio92/yet-another-profiler#4