Remove README text which is no longer relevant after PR #307

Author: JackKelly

README.md

@@ -32,25 +32,11 @@ conda activate nowcasting_dataset
 pip install -e .
 ```
 
-Note you can install the [pytorch](https://github.com/pytorch/pytorch)
-and [pytorch_lightning](https://github.com/PyTorchLightning/pytorch-lightning) using
-```shell
-pip install -e .[torch]
-```
-but it is only used to create a dataloader for machine learning models, and will not be necessary
-soon (when the dataloader is moved to `nowcasting_dataloader`).
-
-
 ### `pip`
 
 A (probably older) version is also available through `pip install nowcasting-dataset`
 
 
-### `RuntimeError: unable to open shared memory object`
-
-To prevent PyTorch failing with an error like `RuntimeError: unable to open shared memory object </torch_2276740_2849291446> in read-write mode`, edit `/etc/security/limits.conf` as root and add this line: `*		 soft	 nofile		 512000` then log out and log back in again  (see [this issue](https://github.com/openclimatefix/nowcasting_dataset/issues/158) for more details).
-
-
 ### PV Live API
 If you want to also install [PVLive](https://github.com/SheffieldSolar/PV_Live-API) then use `pip install git+https://github.com/SheffieldSolar/PV_Live-API
 `