ci: fix user in script

.ci/docs.sh

@@ -9,7 +9,7 @@ if [ "$(id -u)" = 0 ]; then
 	set -x
 	apk -q add \
 		py3-sphinx_rtd_theme 
-	exec su "${TESTUSER:-build}" -c "sh -e $0"
+	exec su "${TESTUSER:-pmos}" -c "sh -e $0"
 fi
 
 # Require sphinx to be installed on the host system