[new release] h2 (7 packages) (0.13.0)
CHANGES:
- h2: surface (body) write failures through `flush`
([anmonteiro/ocaml-h2#247](https://github.com/anmonteiro/ocaml-h2/pull/247))
- `Body.Writer.flush` now takes a callback of the type
``([ `Written | ` Closed] -> unit)``, informing the caller whether the
previous writes have been written or whether the output channel was
closed.