Support for CRAM v3.1
I've looked through the documentation, but I don't see any explicit list on `mosdepth` or `hts-nim`. However, when I try to run `mosdepth` on a v3.1 CRAM file, I get decoding errors. These v3.1 CRAM files work fine with other software. `mosdepth` also works fine when I use a v3.0 CRAM file for the sample. Can you clarify if `mosdepth` 0.3.6 supports v3.1 CRAM files?

```
[E::cram_next_slice] Failure to decode slice
[hts-nim] error:-2 in bam.queryi for tid:0 0..248956422
[E::cram_next_slice] Failure to decode slice
[hts-nim] error:-2 in bam.queryi for tid:1 0..242193529
[E::cram_next_slice] Failure to decode slice
[hts-nim] error:-2 in bam.queryi for tid:2 0..198295559
[E::cram_next_slice] Failure to decode slice
[hts-nim] error:-2 in bam.queryi for tid:3 0..190214555
```