umqtt.robust is missing an example file

[mlpilla]

In line 23 of umqtt.robust/example_sub_robust.py, there is a mention of example_reset_session.py. I could not find this file.

[jonnor]

No-one has found the file in 5 years. Then it is probably not surfacing now, unfortunately. Proposing to close this issue.

[projectgus]

I think the least we can do here is remove the reference to the missing example. If someone wants to contribute an example of how to do this in the future then it would be very welcome.

[dpgeorge]

It looks like this file was just not added to the original commit back in 6190cec (it's easy to forget to git add <newfile> ...).