Document how to use venv to build

.gitignore

@@ -6,11 +6,6 @@ __pycache__
 dist
 vppcfg.egg-info
 .pybuild
-debian/vppcfg
-debian/vppcfg.*.log
-debian/vppcfg.*.debhelper
-debian/.debhelper
-debian/files
-debian/vppcfg.substvars
 .*.~undo-tree~
 .eggs
+.venv/

Makefile

@@ -16,7 +16,7 @@ build:
 
 .PHONY: install-deps
 install-deps:
-	sudo $(PIP) install $(PIP_DEPENDS)
+	$(PIP) install $(PIP_DEPENDS)
 
 .PHONY: install
 install:

README.md

@@ -14,6 +14,11 @@ This program expects Python3 and PIP to be installed. It's known to work on Debi
 Bookworm, as well as on Ubuntu Focal, Jammy and Noble.
 
 ```
+
+## Start a Virtual Environment
+python3 -m venv .venv
+source .venv/bin/activate
+
 ## Install python build dependencies 
 $ make install-deps
 
@@ -23,6 +28,9 @@ $ make test
 ## Build vppcfg
 $ make build
 
+## Exit the virtual environment
+$ deactivate
+
 ## Install the tool with PIP
 $ make install
 ```