Use pip==20.2.4 in tox venv

pip 20.3 is disruptive and would lead to big changes in stable
branches.

Change-Id: I33079e7d667e42240fcc497d595509e88da3c4f7
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 466c415a8..c6d7a4ab2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,6 +2,7 @@
 envlist = docs,pep8,pylint,yamllint,ansiblelint,bashate,bandit,py38,cover,perm
 
 [testenv]
+pip_version = pip==20.2.4
 usedevelop = True
 deps =
   -c{toxinidir}/upper-constraints.txt