fix wording

Author: ezekg

README.md

@@ -4,7 +4,7 @@
 
 Relay is an offline-first on-premise licensing server backed by [Keygen](https://keygen.sh).
 Use Relay to securely manage distribution of cryptographically signed and
-encrypted license files across nodes in offline or air-gapped environments.
+encrypted license files across nodes in an offline or air-gapped environment.
 Relay does not require or utilize an internet connection — it is meant to be
 used in offline or air-gapped networks.