d/changelog: generate entry for 0.0.8-4 stretch-wikimedia

New changelog entry.

Change-Id: I4ca2b36b48e1b7d116952b20817ad2c4c2f483d7
Git-Dch: Ignore
Bug: T215605
Signed-off-by: Arturo Borrero Gonzalez <aborrero@wikimedia.org>

debian/changelog

+prometheus-openstack-exporter (0.0.8-4) unstable; urgency=medium
+
+  * [646f2be] src:prometheus-openstack-exporter: run wrap-and-sort
+  * [766fa1b] src:prometheus-openstack-exporter: bump debhelper compat to 10
+  * [e26a03c] postinst: use non-existent home dir
+  * [dd4dd61] src:prometheus-openstack-exporter: bump std-versions to 3.9.8
+  * [f69003d] src:prometheus-openstack-exporter: switch to python3
+
+ -- Arturo Borrero Gonzalez <aborrero@wikimedia.org>  Fri, 08 Feb 2019 18:21:16 +0100
+
 prometheus-openstack-exporter (0.0.8-3) jessie-wikimedia; urgency=medium
 
   * [fcbe41f] d/dirs: include /var/cache/prometheus-openstack-exporter