add bin/dnet/python-venv to .gitignore and standadize naming in dnet README

.gitignore

@@ -42,6 +42,7 @@ python-venv
 /darkwikid
 /zktool
 /riscv-bins
+/bin/dnet/python-venv
 
 # tags, ctags, rusty-tags
 TAGS

bin/dnet/README.md

@@ -19,19 +19,19 @@ Depending on your setup you may need to install a virtual environment
 for Python. Do so as follows:
 
 ```shell
-% python -m venv env
+% python -m venv python-venv
 ```
 
 Then install the requirements:
 
 ```shell
-% env/bin/pip install -r requirements.txt
+% python-venv/bin/pip install -r requirements.txt
 ```
 
 Run dnet:
 
 ```shell
-% env/bin/python main.py
+% python-venv/bin/python main.py
 ```
 
 ### Without a venv