fix: Maintain backward compatibility with older bench versions (#31542)

Older versions of bench depend on `name` in setup.py

Setting it to `frappe` causes some weird behavior like moving `apps/erpnext` to `apps/frappe`
diff --git a/setup.py b/setup.py
index 0ea4d07..29fa1c7 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 # TODO: Remove this file when  v15.0.0 is released
 from setuptools import setup
 
-name = "frappe"
+name = "erpnext"
 
 setup()