chore(deps): update netdata/netdata docker tag to v2.7.3 (#37)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build-images.sh

@@ -40,7 +40,7 @@ buildah config --entrypoint=/ \
     --label="org.nethserver.tcp-ports-demand=1" \
     --label="org.nethserver.rootfull=1" \
     --label="org.nethserver.flags=no_data_backup" \
-    --label="org.nethserver.images=docker.io/netdata/netdata:v2.7.2" \
+    --label="org.nethserver.images=docker.io/netdata/netdata:v2.7.3" \
     "${container}"
 # Commit the image
 buildah commit "${container}" "${repobase}/${reponame}"