smtp/connection: fix custom log fn assignment

smtp/connection.ts

@@ -183,7 +183,7 @@ export class SMTPConnection extends EventEmitter {
 		this.password = () => password as string;
 
 		if (typeof logger === 'function') {
-			this.log = log;
+			this.log = logger;
 		}
 	}
 

test/connection.ts

@@ -0,0 +1,11 @@
+import test from 'ava';
+
+import { SMTPConnection } from '../email.js';
+
+test('accepts a custom logger', async (t) => {
+	const logger = () => {
+		/** ø */
+	};
+	const connection = new SMTPConnection({ logger });
+	t.is(Reflect.get(connection, 'log'), logger);
+});