Unfortunately, nothing works.
In the first case  with this change : self.fc2 = nn.Linear([fc1_units] + action_size, fc2_units)
I get this error

File “C:\Users\Danae\Anaconda3\envs\effort7\lib\site-packages\torch\nn\modules\linear.py”, line 41, in init
self.weight = Parameter(torch.Tensor(out_features, in_features))
TypeError: ‘list’ object cannot be interpreted as an integer

and with this change self.fc2 = nn.Linear(fc1_units + action_size[0], fc2_units)
I get this error

File “C:\Users\Danae\Anaconda3\envs\effort7\lib\site-packages\torch\nn\modules\linear.py”, line 41, in init
self.weight = Parameter(torch.Tensor(out_features, in_features))
RuntimeError: CUDA error (35): CUDA driver version is insufficient for CUDA runtime version