helpers/new_release.sh: make sure release commit is signed

helpers/new_release.sh

@@ -223,7 +223,7 @@ release() {
 		feeds_conf_set "$feed" "${FEEDS["$feed"]}"
 	done
 	git add ./feeds.conf
-	_release_git commit -m "Turris OS $tversion" --date="$RELEASE_DATE" -m "$(./helpers/turris-version.sh news)"
+	_release_git commit -S -m "Turris OS $tversion" --date="$RELEASE_DATE" -m "$(./helpers/turris-version.sh news)"
 	_release_git tag -s -m "Turris OS $tversion release" -m "$(./helpers/turris-version.sh news)" "v$tversion"
 
 	info "Tag $tag was created. Review changes and push it with: git push origin $tag"