Mach is deprecated, update to mach2

[ameknite]

Using cargo deny, I found that 'mach' is unmaintained. I suggest using 'mach2,' a fork that is maintained, instead of 'mach'. fitzgen/mach#63 (comment)

error[unmaintained]: mach is unmaintained
  ┌─ /slice_ring_buffer/Cargo.lock:2:1
  │
2 │ mach 0.3.2 registry+https://github.com/rust-lang/crates.io-index
  │ ---------------------------------------------------------------- unmaintained advisory detected
  │
  = ID: RUSTSEC-2020-0168
  = Advisory: https://rustsec.org/advisories/RUSTSEC-2020-0168
  = Last release was almost 4 years ago.
    
    Maintainer(s) seem to be completely unreachable. 
    
    ## Possible Alternative(s)
    
    These may or may not be suitable alternatives and have not been vetted in any way;
    - [mach2](https://crates.io/crates/mach2) - direct fork
  = Announcement: https://github.com/fitzgen/mach/issues/63
  = Solution: No safe upgrade is available!
  = mach v0.3.2
    └── slice-ring-buffer v0.3.2

advisories FAILED, bans ok, licenses ok, sources ok
``` is unmaintained,

[ameknite]

Also, pls publish a new version if this get merge

[LiquidityC]

Looks like the project has become slightly stale. I'll take a look at fixing up clippy and digging into what happened to the mips toolchain. Hopefully it's simple stuff.

[ameknite]

@LiquidityC any updates?

[LiquidityC]

Yes. I'm sorry. Been swamped with work. I'll get to it ASAP.

[LiquidityC]

Those toolchains are "Tier 3" so I just dropped them to allow CI to pass. Pending my PR here #8

[LiquidityC]

You should be able to rebase now. Besides that there's a formatting warning in your CI run. Once those things are fixed we can merge.
The CI seems generally unstable. I myself don't have the time to dive into it at the moment so we'll just have to fiddle until it passes.

[ameknite]

I rebase and fix the fmt, I hope now it can be merged