MAINT: Tidy up environment.yml

This changes the environment name to `npf-dev` and
removes the duplicate entry for asv.

Author: Kai-Striega

environment.yml

@@ -1,8 +1,8 @@
 # To use:
 #   $ conda env create -f environment.yml  # `mamba` works too for this command
-#   $ conda activate numpy-financial-dev
+#   $ conda activate npf-dev
 #
-name: numpy-financial-dev
+name: npf-dev
 channels:
   - conda-forge
 dependencies:
@@ -20,7 +20,6 @@ dependencies:
   # Tests
   - pytest
   - pytest-xdist
-  - asv>=0.6.0
   - hypothesis
   # Docs
   - myst-parser