Ecole

Bug fixes
- Fix version number in version file

Bug fixes
- env.reset now copies the model problem definition using [`SCIPcopyOrig`](https://scipopt.org/doc-7.0.1/html/group__CopyMethods.php#gad4caa853ecbc0446cd90e31c798406f5) to allow user to reuse instance from instance generators.
- Change loggin level to `debug` in `CombinatorialAuctionGenerator`.

Bug fixes
- Fix Python files sometimes not being added in CMake build

New features
- Add `InformationFunction` to configure the content of the info dictionary returned in `Environment`
- Add `SolvingTime` reward function

Breaking changes
- For observation and reward function, `reset` has been renamed `before_reset`, and consequently called right before `reset_dynamics`
- `Environment.reset` return the information dictionary as a fifth parameter.

New features
- Add new `instance` module with `SetCover`, `CapacitatedFacilityLocation`, `IndependentSet`, and `CombinatorialAuction` generator (implemented in Python).
- Add main source of randomness and `ecole.seed(val)` function for default random state (except in instance genertaors, upcoming) f3b68ca

Breaking changes
- Minimum C++ version moved to C++17 4d3d631
- Upgrade to Pybind 2.6 8879694