Support uuid v1 and arrayvec 0.7

[GREsau]

Supersedes #138

Support for the new versions of these crates is added in a backward-compatible way - the arrayvec and uuid features will still implement JsonSchema for types in previous versions of those crates.

The new crate versions can be used by enabling the uuid1 and arrayvec07 features. When I next make breaking changes to schemars, I'll probably change the uuid feature to behave the same as uuid1, since it's highly unlikely there will be a v2 of uuid according to its release notes. I will probably just remove the arrayvec feature, unless its maintainers announce they don't expect breaking changes.

This PR does not add any support for arrayvec 0.6, since no-one has asked for it as far as I know.

This change also updates dev dependencies and serde_derive_internals.

It's probably worth taking a look at the other optional dependencies, judging whether they're likely to have breaking changes in future, and if so, add version suffixes to their corresponding feature flags.

Documentation (including readme) still needs updating before merging!

[jhpratt]

Diff LGTM

[ahl]

Thanks for doing this; do you think this warrants an update to the README to explain the situation?

[GREsau]

do you think this warrants an update to the README to explain the situation?

I've documented the new flags in the README, and mentioned the deprecation of previous feature flags in the changelog, which hopefully is enough for now

[GREsau]

Published to crates.io in schemars 0.8.9 🎉

[ahl]

This ship may have sailed, but would it work to simply change the dependency on uuid:

@@ -21,7 +21,7 @@ dyn-clone = "1.0"
 chrono = { version = "0.4", default-features = false, optional = true }
 indexmap = { version = "1.2", features=["serde-1"], optional = true }
 either = { version = "1.3", default-features = false, optional = true }
-uuid = { version = "0.8", default-features = false, optional = true }
+uuid = { version = ">=0.8.0, <2.0.0", default-features = false, optional = true }
 smallvec = { version = "1.0", optional = true }
 arrayvec = { version = "0.5", default-features = false, optional = true }
 url = { version = "2.0", default-features = false, optional = true }

I'm pretty sure that the use of uuid is compatible across those versions (and probably even farther back than 0.8)

This would make things much simpler for consumers of schemars