[#8557] Upgrade python-dateutil 2.8.2 -> 2.9.0. (OUTDATED! latest is: 2.9.0.post0), and its deps: six

    python-dateutil                   2.8.2 -> 2.9.0. (OUTDATED! latest is: 2.9.0.post0)
        six                          1.16.0 -> no upgrade
diff --git a/requirements.txt b/requirements.txt
index 618b179..46f4634 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -169,7 +169,7 @@
     # via -r requirements.in
 pytest-xdist==3.5.0
     # via -r requirements.in
-python-dateutil==2.8.2
+python-dateutil==2.9.0.post0
     # via
     #   -r requirements.in
     #   easywidgets