automation: install python3-venv Debian package
Debian's python install has a crippled venv by default, as it is
lacking ensurepip. When you try to run `python3 -m venv` it tells
you to install `python3-venv`. So this commit does that in our
automation environment so we can fully test installing Mercurial
using venv+pip with the system Python.
Differential Revision: https://phab.mercurial-scm.org/D7229
--- a/contrib/automation/hgautomation/linux.py Mon Nov 04 23:42:18 2019 -0800
+++ b/contrib/automation/hgautomation/linux.py Mon Nov 04 23:44:10 2019 -0800
@@ -266,6 +266,7 @@
python3-fuzzywuzzy \
python3-pygments \
python3-vcr \
+ python3-venv \
rsync \
sqlite3 \
subversion \