README: Add xor-gate as author

README.md

diff --git a/README.md b/README.md
index 1309153..83310e5 100644
--- a/README.md
+++ b/README.md
@@ -366,6 +366,7 @@
 * [spf13](https://github.com/spf13)
 * [jaqx0r](https://github.com/jaqx0r)
 * [mbertschler](https://github.com/mbertschler)
+* [xor-gate](https://github.com/xor-gate)
 
 ## License