lib/container: Add APIs to retrieve version conveniently

[cgwalters]

This also relates to youki-dev/oci-spec-rs#143

Basically getting the version from the config requires a helper, this is a lot more convenient.

[cgwalters]

Well that's exciting

thread 'rustc' panicked at 'assertion failed: Vec::len(self) == i', /builddir/build/BUILD/rustc-1.72.1-src/vendor/ena/src/snapshot_vec.rs:53:17

thread 'rustc' panicked at 'assertion failed: Vec::len(self) == i', /builddir/build/BUILD/rustc-1.72.1-src/vendor/ena/src/snapshot_vec.rs:53:17
stack backtrace:
   0:     0x7f2756bc20c1 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h35073a9e56bccd9e
   1:     0x7f2756c26eef - core::fmt::write::h5f7e0780d5d3bf57
   2:     0x7f2756bb5ef9 - <unknown>
   3:     0x7f2756bc1ed5 - <unknown>
   4:     0x7f2756bc4cb3 - <unknown>
   5:     0x7f2756bc4a44 - std::panicking::default_hook::h4db4f15e70760494
   6:     0x7f275748884b - <unknown>
   7:     0x7f2756bc546e - std::panicking::rust_panic_with_hook::h05b3acb3dfba5d03
   8:     0x7f2756bc51b1 - <unknown>
   9:     0x7f2756bc2526 - <unknown>
  10:     0x7f2756bc4f42 - rust_begin_unwind
  11:     0x7f2756b85753 - core::panicking::panic_fmt::h8cf040903fbd6815
  12:     0x7f2756b857e3 - core::panicking::panic::h2193f8fbbe16bdc6
  13:     0x7f27597bc243 - <rustc_infer[8a4aeedcac035534]::infer::type_variable::TypeVariableStorage as ena[6bbeec23d1e1bf7]::undo_log::Rollback<rustc_infer[8a4aeedcac035534]::infer::type_variable::UndoLog>>::reverse
  14:     0x7f2759812bc8 - <rustc_infer[8a4aeedcac035534]::infer::InferCtxtInner as ena[6bbeec23d1e1bf7]::undo_log::Rollback<rustc_infer[8a4aeedcac035534]::infer::undo_log::UndoLog>>::reverse
  15:     0x7f2759812fbf - <rustc_infer[8a4aeedcac035534]::infer::InferCtxtInner>::rollback_to
  16:     0x7f275981aa28 - <rustc_infer[8a4aeedcac035534]::infer::InferCtxt>::rollback_to
  17:     0x7f27579a3af8 - <unknown>
  18:     0x7f27579d74bc - <unknown>
  19:     0x7f27579a39e8 - <unknown>
  20:     0x7f27578c3a11 - <rustc_hir_typeck[8441c98fd11c7262]::fn_ctxt::FnCtxt>::try_coerce
  21:     0x7f27579dc4a8 - <unknown>
  22:     0x7f27578f6c8a - <unknown>
  23:     0x7f2757935faa - <unknown>
  24:     0x7f27578d53e3 - <unknown>
  25:     0x7f27578d68b8 - <unknown>
  26:     0x7f2757a7b79a - <unknown>
  27:     0x7f27579ffea9 - <unknown>
  28:     0x7f275890a33c - <unknown>
  29:     0x7f275897133c - <unknown>
  30:     0x7f2758bc0f63 - <unknown>
  31:     0x7f2758a1abf7 - <unknown>
  32:     0x7f27579ff795 - <unknown>
  33:     0x7f27589080ec - <unknown>
  34:     0x7f275899c8ec - <unknown>
  35:     0x7f2758bc0f63 - <unknown>
  36:     0x7f27589444f7 - <unknown>
  37:     0x7f2757b1f189 - <unknown>
  38:     0x7f2757c867b9 - rustc_hir_analysis[890cb7f811e6521a]::check_crate
  39:     0x7f275767d1e1 - rustc_interface[4325c0f328fc5299]::passes::analysis
  40:     0x7f275890a3aa - <unknown>
  41:     0x7f2758aaaae8 - <unknown>
  42:     0x7f2758b53dd3 - <unknown>
  43:     0x7f2758942993 - <unknown>
  44:     0x7f27574e1eaa - <unknown>
  45:     0x7f27574974a5 - <unknown>
  46:     0x7f27574d89d1 - <unknown>
  47:     0x7f27574ce2c3 - <unknown>
  48:     0x7f27574b90b9 - <unknown>
  49:     0x7f27574de021 - <unknown>
  50:     0x7f2756bcfad5 - <unknown>
  51:     0x7f27569c5947 - start_thread
  52:     0x7f2756a4b774 - __clone
  53:                0x0 - <unknown>

Searching around there are some related issues like rust-lang/rust#114056 but not an exact match seemingly?

I think this is probably an incremental compilation bug, will look at flushing our caches.

[cgwalters]

Yep, flushing the cache and restarting worked.

[jmarrero]

lgtm