Update paho-mqtt-sys package

[bioxz]

This PR updates the paho-mqtt-sys version to 10.0.3 (from 10.0.1) providing support for current compilers (see Releases sys-v0.10.3 / eclipse-paho/paho.mqtt.rust#249).

[sophokles73]

Thanks a lot for the PR. However, updating the dependency in Cargo.lock does not look like a sustainable fix for the issue, because this repo's Cargo.lock is not part of the crate published on crates.io (and is also not considered by code depending on this crate).

FMPOV we will simply need to wait for the next version of the paho-mqtt crate that we depend upon, which should include the fixed paho-mqtt-sys crate as well ...

[bioxz]

Ah, okay. As 0.3.0 wasn't published when I opened this PR I built this crate from a local path, thus the Cargo.lock was relevant for me. I have to admit that I'm not really knowledgeable about building creates for crates.io, but was under the assumption that it should be possible to download and build this repository as well (e.g. the GitHub actions do that and would fail if ubuntu-latest would get updated).

Thank you for the response, for my use case I can now go with the released 0.3.0 crate.