`.prototools` should allow `[versions]` header about proto

[milesj]

This actually seems to be a bug in our serde impl. The versions field uses #[serde(flatten)] but it doesn't flatten when serializing. Need to figure out why.

I don't really want to support 2 ways of configuring the versions though.

[milesj]

Figured out the serde problem

[rotu]

Need to figure out why.

We have two flatten fields, one of them with #[serde(skip_serializing)] and I'm guessing that's the why.

proto/crates/core/src/proto_config.rs

Lines 98 to 103 in 7bf0abc

	#[setting(flatten, merge = merge::merge_btreemap)]
	pub versions: BTreeMap<Id, UnresolvedVersionSpec>,
	#[setting(flatten, merge = merge::merge_btreemap)]
	#[serde(skip_serializing)]
	pub unknown: BTreeMap<String, TomlValue>,

Maybe we should have a custom deserializer for the unknown field to update the versions property instead of massaging the struct after deserialization.

Possibly related? serde-rs/serde#1504

[rotu]

The bug part of this is fixed :-). If you think it's not worth changing the toml, you can of course close this issue.

[milesj]

Looked into this a bit and it made it rather difficult to support both patterns.