Add license file for phpmd ruleset

diff --git a/.phpmd-ruleset.xml.license b/.phpmd-ruleset.xml.license
new file mode 100644 (file)
index 0000000..985c307
--- /dev/null
+++ b/.phpmd-ruleset.xml.license
@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2010-2024 the Friendica project
+
+SPDX-License-Identifier: CC0-1.0