Add support for 7.x

[Daniel-B-Smith]

Opening an issue since I'm about to start working on this and to get feedback before any PRs are sent out.

It looks like there are a couple of pieces added to the C API in 7.0: apple/foundationdb#2644 The change to keyvalue from void* to uint8_t* made it in, so that may require a change to the generated interface. I'm actively working on apple/foundationdb#2644, but that probably won't make it in until 7.1.

[Speedy37]

The change to keyvalue from void* to uint8_t* made it in, so that may require a change to the generated interface.

I just made a change to prevent issues related to this: 129a688

We are generating both options.rs and foundationdb_sys from fdb.options and fdb_cli.h so we should already be quite safe to catch any breaking change at compile time.

[Daniel-B-Smith]

That's great. All of the other changes to the C API should be strictly additive.

[PierreZ]

Are you working on this feature @Daniel-B-Smith? I just pushed a PR for 6.3, and I was thinking about doing 7.X next.

[Daniel-B-Smith]

I am not.

[PierreZ]

Okay, I will try to open a 7.X PR once a pre-release is tagged.

[PierreZ]

Initial work around api 700 can be found here