Update to version 1.8.0

[BDonnot]

Breaking changes

• now requires numpy >= 1.20 to work (otherwise there are
  issues with newer versions of pandas).
• issue check_env function of gym is giving some assertion errors after converting environment using GymEnv #379 requires
  different behaviour depending on installed gym package.
• cooldowns are not consistent between env.step and obs.simulate.
  If obs.time_before_cooldown_line[l_id] > 0 it will be illegal, at the next call to env.step
  (and obs.simulate) to modify the status of this powerline l_id. Same for
  obs.time_before_cooldown_sub[s_id] > 0 if trying to modify topology of
  substation s_id. This also impacts the maintenances and hazards.
  This is also linked to github issue Line that will be in maintenance next time step are not taken into account in the "simulate" function #148

Fixed issues

• a bug when using a Runner with an environment that has
  been copied (see Environment object has no attribute '_is_test' #361)
• issue A package should not be present #358
• issue Environment to_test referenced before assignment #363
• issue Bug: Wrong changed status on BaseActio.impact_on_objects() for curtailment #364
• issue Error occurs while training with rllib ray PPO #365 and
  Enable to load grid2op data with pickle #376 . Now the function(s)
  gridobj.process_shunt_data and gridobj.process_grid2op_shunt_data are called
  gridobj.process_shunt_static_data
• issue actual_dispatch added to target_dispatch when the previous target_dispatch is 0 but actual_dispatch is not #367
• issue Wrong observation's start date with the MultifolderWithCache chronic class and the l2rpn_wcci_2022 env #369
• issue obs.simulate and env.step check cooldown differently #374
• issue Simulator rho values not correct after calling sim.predict() #377 by adding a special
  method backend.update_thermal_limit_from_vect

Addition

• the "packaging" python package is now required to install grid2op.
  It allows to support different gym versions that changes behavior regarding
  numpy pseudo random generator.
• the function act.remove_line_status_from_topo to ignore the line status modification
  that would be induced by "set_bus" or "change_bus" when some cooldown applies on the powerline.

Improvement

• clarify documentation of gym compat module (see
  Missing DiscreteAction doc  #372 and
  Clarify on read the docs how to customize the action space a'd observation space  #373) as well as the doc
  for MultifolderWithCache (see Improve the explications about the MultifolderWithCache chonic class #370)