CHANGELOG.rst is outdated

### Description
[CHANGELOG.rst](https://github.com/eiffel-community/eiffel-pythonlib/blob/master/CHANGELOG.rst) is outdated and only covers 1.0.0, 1.0.1, and 1.0.2, i.e. it's missing 1.1.0 and 1.1.1. We should either get it up to date or remove it. I don't have a particular opinion on which option is chosen.

### Motivation
Out of date changelogs are like failing tests; fix them or get rid of them.

### Exemplification
N/A

### Benefits
Obvious.

### Possible Drawbacks
None.