docs: add docs.rs badge to readme

[philpax]

When looking at a crate's README, I usually look for the docs.rs badge at the top, and assume that it doesn't have docs otherwise. I thought that was initially the case with wonnx, but then I noticed the link to the docs later in the readme. Figured I'd add the badge to stop others from making the same assumption I did 👌

[haixuanTao]

Thanks :)

[haixuanTao]

Just for info, I'm not sure if the doc on docs.rs is up to date. :S sorry

[pixelspark]

It is, but for the last released crate (v0.2.4, 7 months old). We should release a new one!

[SludgePhD]

There have been many breaking changes since 0.2.4, so the new version should have been 0.3, not 0.2.5

[pixelspark]

There have been many breaking changes since 0.2.4, so the new version should have been 0.3, not 0.2.5

Not according to semantic versioning: for major version zero (0.x.y), anything may change at any time, public API is not considered stable. Cargo specifically implements SemVer logic, but does consider versions 0.X.Y compatible when X is equal.

Publishing v0.3.0 and yanking v0.2.5 would still be legal according to SemVer and would not break users relying on X<0 compatibility. While I personally frown upon cargo's deviance from SemVer here, I would be fine with doing it this way.

[pixelspark]

@SludgePhD v0.2.5 now yanked, v0.3.0 published.

[SludgePhD]

Yeah, sadly not doing what Cargo does here would wreak havoc on all downstream crates, so there's not much of a choice