Reenable Jessie images
Manually install python3-junit.xml
package from Stretch in Jessie lintian
image.
Background: In Debian the Debian LTS Security Team, we recently started thinking about using Salsa-CI for more automated testing. Therefore it would be very helpful to keep Jessie versions of the Salsa-CI container images available as long as Jessie is supported by Debian LTS.