Merge branch 'nanonyme/18.08-metadata' into '18.08'

Backport simpler date calculation just in case

See merge request !1262

.gitlab-ci.yml

@@ -107,7 +107,7 @@ before_script:
 
   - |
     if [ -n "$GENERATE_VERSION" ]; then
-      timestamp=$(git describe | git rev-parse |xargs git log -1 --format="%at")
+      timestamp=$(git log -1 --format="%at" ${CI_COMMIT_SHA1})
       cat >version.yml <<EOF
     variables:
       runtime-version: '$(git describe | sed 's/^freedesktop-sdk-//')'