Install systemd-python from distribution package

CentOS 8 support start to fail because of an issue [1]
compiling systemd python binding modules.
Let install it from distribution packages as documented by
python-systemd project Web page [2]

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1862714
[2] https://github.com/systemd/python-systemd

Closes-Bug: #1908386
Change-Id: Ic7cfd72ce1b875e75b1cdbdd44a902b25d51abb8
diff --git a/files/debs/general b/files/debs/general
index 4bf1ff4..d64417f 100644
--- a/files/debs/general
+++ b/files/debs/general
@@ -28,6 +28,7 @@
 psmisc
 python3-dev
 python3-pip
+python3-systemd
 python3-venv
 tar
 tcpdump