commit a0d20514c6ebbfe6b42b989b6192ae77312d3ba7
Author: Nicolas Bock <nicolas.bock@canonical.com>
Date:   Wed Sep 30 12:10:26 2020 -0600

    Increase lower-constraint for kombu
    
    There is no module named 'vine' on kombu==4.1.0 version [1]. Bumping
    to kombu-4.2.1 (and not kombu-4.2.0) [2].
    
    [1] https://github.com/celery/kombu/issues/851
    [2] https://docs.celeryproject.org/projects/kombu/en/stable/changelog.html#version-4-2-1
    
    Change-Id: I57a7649fde1cceda787622aa1975f3a7100aeb29
    Signed-off-by: Nicolas Bock <nicolas.bock@canonical.com>

diff --git a/lower-constraints.txt b/lower-constraints.txt
index d61be6d..c0042b9 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -52,7 +52,7 @@ jsonschema==3.2.0
 kazoo==2.6.0
 keystoneauth1==3.4.0
 keystonemiddleware==4.17.0
-kombu==4.1.0
+kombu==4.2.1
 linecache2==1.0.0
 logutils==0.3.5
 Mako==1.0.7