[tests] Update dependencies

- add packaging to requirements
- Use Python 3.8 to run the tests;
  otherwise importlib_metadata would be required

Bug: T354325
Change-Id: Id731f69765826fcb9e64d6b58dd9993c9626869f
---
M tox.ini
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tox.ini b/tox.ini
index 732623c..403d987 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,12 +7,13 @@
 skip_missing_interpreters = True
 
 # Environments to execute when invoking 'tox'
-envlist = py37
+envlist = py38
 
 [testenv]
 commands = ./run-tests.sh {envtmpdir}
 
 deps =
+    packaging
     requests
     wikitextparser
 allowlist_externals = *

