Use venv module rather than virtualenv

- simpler to use
- lighter dependency (or no dependency at all, depending on python distribution)
- retrocompatible

virtualenv package from pip to acheive virtual environment feature is no longer
needed, except for projects which need to support py2, which is no longer our
case.

Also, reword "virtualenv" to "virtual environment" in doc, to avoid confusion
with pip package name.

Ref #483

1 files changed, 1 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index a681709..e2fbf32 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-VIRTUALENV = virtualenv --python=python3
+VIRTUALENV = python3 -m venv
 SPHINX_BUILDDIR = docs/_build
 VENV := $(shell realpath $${VIRTUAL_ENV-.venv})
 PYTHON = $(VENV)/bin/python3