Jenkins: add our CI repo as well

It was manually created before

install_jenkins.yml

@@ -42,6 +42,10 @@
     - role: gbp
       gbp_cowbuilder_targets:
         - dist: buster
+        - dist: buster
+          autoconf: False
+          basepath: /var/cache/pbuilder/base-buster+ci.cow
+          pbuilder_options: "--dist=buster --keyring=/etc/pbuilder/keyrings/ci-repo.gpg --othermirror='deb http://ci.puri.sm/ plamoci librem5'"
         - dist: buster
           autoconf: False
           basepath: /var/cache/pbuilder/base-buster+plamo.cow