Add .asf.yml

As described here: https://s.apache.org/asfyamlpublishing
diff --git a/.asf.yml b/.asf.yml
new file mode 100644
index 0000000..0735550
--- /dev/null
+++ b/.asf.yml
@@ -0,0 +1,2 @@
+publish:
+  whoami: asf-site