Apply ruff/flake8-import-conventions (ICN)

ICN001 `numpy` should be imported as `np`

Author: DimitriPapadopoulos

setup.py

@@ -197,13 +197,13 @@ def lz4_extension():
 
 def vlen_extension():
     info('setting up vlen extension')
-    import numpy
+    import numpy as np
 
     extra_compile_args = base_compile_args.copy()
     define_macros = []
 
     # setup sources
-    include_dirs = ['numcodecs', numpy.get_include()]
+    include_dirs = ['numcodecs', np.get_include()]
     # define_macros += [('CYTHON_TRACE', '1')]
 
     sources = ['numcodecs/vlen.pyx']