Update igraph

[vtraag]

This updates libleidenalg to work with igraph 1.0. This still requires to update the constraints to work with a new Python release of python-igraph, but this is not yet available. We should wait until that is release before releasing a new version of leidenalg to work with igraph 1.0.

[vtraag]

This fixes #208

[vtraag]

FYI, the CI failures are most likely due to incompatabilities between the current python-igraph version being used (which still relies on an igraph C core 0.10) and the leidenalg (which is already using igraph C core 1.0). Once a new python-igraph release is available, we can bump the version constraints in order to ensure they are compatible.

[dotlambda]

Once a new python-igraph release is available, we can bump the version constraints in order to ensure they are compatible.

https://github.com/igraph/python-igraph/releases/tag/1.0.0 was released

[vtraag]

I'll now merge this, CI should pass.