add correct versions of rtic_bare exercises

examples/rtic_bare1.rs

examples/rtic_bare2.rs

examples/rtic_bare3.rs

examples/rtic_bare4.rs

examples/rtic_bare5.rs

examples/rtic_bare6.rs

examples/rtic_bare7.rs

examples/rtic_bare8.rs

examples/rtic_bare9.rs