Release v1.9.6

• [BREAKING] when a storage is connected alone on a bus, even if it produces / absorbs 0.0 MW it
  will raise a diverging powerflow error (previously the storage was automatically disconnected by
  PandaPowerBackend, but probably not by other backends)
• [BREAKING] when a shunt is alone on a bus, the powerflow will diverge even in DC mode
  (previously it only converges which was wrong behaviour: grid2op should not disconnect shunt)
• [FIXED] a bug in PandaPowerBackend (DC mode) where isolated load did not raised
  exception (they should lead to a divergence)
• [FIXED] some wrong behaviour in the remove_line_status_from_topo when no observation where provided
  and check_cooldown is False
• [FIXED] a bug in PandaPowerBackend in AC powerflow: disconnected storage unit had no 0. as voltage
• [FIXED] a bug in PandaPowerBackend in AC powerflow when a generator was alone a bus it made the powerflow
  crash on some cases (eg without lightsim2grid, without numba)
• [FIXED] a bug in PandaPowerBackend in DC (in some cases non connected grid were not spotted)
• [FIXED] now the observations once reloaded have the correct _is_done flag (obs._is_done = False)
  which allows to use the obs.get_energy_graph() for example. This fixes #538
• [ADDED] now depends on the typing_extensions package
• [ADDED] a complete test suite to help people develop new backend using "Test Driven Programming"
  techniques
• [ADDED] the information on which time series data has been used by the environment in the inforeturn value
  of env.step(...)
• [ADDED] a test suite easy to set up to test the backend API (and only the backend for now, integration tests with
  runner and environment will follow)
• [ADDED] an attribute of the backend to specify which file extension can be processed by it. Environment creation will
  fail if none are found. See backend.supported_grid_format see #429
• [IMPROVED] now easier than ever to run the grid2op test suite with a new backend (for relevant tests)
• [IMPROVED] type hints for Backend and PandapowerBackend
• [IMPROVED] distribute python 3.12 wheel
• [IMPROVED] test for python 3.12 and numpy 1.26 when appropriate (eg when numpy version is released)
• [IMPROVED] handling of environments without shunts
• [IMPROVED] error messages when grid is not consistent
• [IMPROVED] add the default l2rpn_case14_sandbox environment in all part of the docs (substituing rte_case14_realistic or nothing)
• [IMPROVED] imports on the Exceptions module
• [IMPROVED] pandapower backend raises BackendError when "diverging"