redbpf-probes build script failure

[rhdxmr]

The build script of redbpf-probes 2.0 exits abnormally with this error.

error: header '../bpf-sys/libbpf/src/bpf_helpers.h' does not exist.

This happens when the redbpf-probes dependency is defined only with a version number.

I found that a copy of bpf_helpers.h was removed from redbpf-probes by c33138d on May 10.

I could not run into this issue before redbpf-probes 2.0 was released to crates.io
because everything's ok with the redbpf-probes dependency if it is defined by using a path = option.