Add script to check for API breaks

[fabianfett]

We should check for API breaking changes in CI, to ensure we don't accidentally break API going forwards.

Motivation:

• We should check for API breaking changes in CI, to ensure we don't accidentally break API going forwards.

Modifications:

• Add a script that checks for breaking changes (copy and pasted from NIO).

Result:

• We ensure we don't accidentally break API after 1.0

Open tasks:

@tomerd we need to add another CI that runs the API checking script.

[tomerd]

thanks @fabianfett, should we add a docker compose task that runs this, or do we need to do that at the CI server level?

nm, added one

[fabianfett]

@tomerd I tried to see what we do in AHC. However I did not find a special docker-compose task for it. So I assume it is activated in the CI server.

[tomerd]

@swift-server-bot test this please

[tomerd]

@swift-server-bot test this please