Release process bugs

[poljar]

• The main crate depends on the ffi-macros crate which isn't part of the release process.

• The generated changelogs don't work well, changes from one crate bleeds into the changelog of another.

• The main crate, when the testing feature is enabled depends on the matrix-sdk-testing crate.

• edit - I hijacked this issue as a general release process bugs issue

[bnjbvr]

The ffi-macros crate is used if the uniffi feature is set, right? So technically we do have to ship it, even though we don't ship the bindings, as long as we have the uniffi feature 🤔

[poljar]

Well yes, that's what this issue is about, I released the macros crate manually this time around.

Though we can do a couple of things to fix this issue:

1. Get rid of the dep.
2. Add the ffi-macros to our release process.
3. Upstream the feature the macro provides to uniffi.