update README.md to reflect new filename

README.md

@@ -91,7 +91,7 @@ $ cd rmm
 - Create the conda development environment `rmm_dev`
 ```bash
 # create the conda environment (assuming in base `rmm` directory)
-$ conda env create --name rmm_dev --file conda/environments/rmm_dev_cuda11.0.yml
+$ conda env create --name rmm_dev --file conda/environments/full_cuda-11.5_arch-$(arch).yaml
 # activate the environment
 $ conda activate rmm_dev
 ```