enh(proxy): make ProxyManager.load return _id_remap

[bourdaisj]

This can be useful when one is restoring a simput state and keeps around the old proxy ids in its own managed state.
This way they can keep both state in sync.

[jourdain]

Looks good but you need to rework your commit message to be compatible with semantic release.

fix(proxy): make ProxyManager.load return _id_remap

[bourdaisj]

Yep, thanks, my bad. Done!