Create major release version 1.0.0

[andreaskring]

Would it be possible to release xmltodict as version 1.0.0?

When using semantic versioning, minor releases < 1.0.0 are considered to be mutual breaking (e.g. 0.14.0 is potentially breaking compared to 0.13.0) and this leads to problems when using Poetry for Python package management, i.e. error like the following can occur:

Because no versions of another-sd-client match >1.1.0,<2.0.0
 and another-sd-client (1.1.0) depends on xmltodict (>=0.13.0,<0.14.0), another-sd-client (>=1.1.0,<2.0.0) requires xmltodict (>=0.13.0,<0.14.0).
So, because sdlon depends on both xmltodict (^0.12.0) and another-sd-client (^1.1.0), version solving failed.

Problems like these could be avoided if xmltodict is release as version 1.0.0.