Mention Sebastien when some changes occur in OpenBSD

Author: JohnTitor

highfive/configs/rust-lang/libc.json

@@ -4,6 +4,12 @@
     },
     "dirs": {
     },
+    "mentions": {
+        "src/unix/bsd/netbsdlike/openbsd": {
+            "message": "Some changes occurred in OpenBSD module",
+            "reviewers": ["@semarie"]
+        }
+    },
     "contributing": "https://github.com/rust-lang/libc/blob/master/CONTRIBUTING.md",
     "new_pr_labels": ["S-waiting-on-review"]
 }