README.md: -e LANG=de --> -e LANG=de \

fix typo in install guide (thanks to @fabiantreu)
Closes: https://github.com/wg-easy/wg-easy/issues/783

README.md

@@ -50,7 +50,7 @@ To automatically install & run wg-easy, simply run:
 <pre>
 $ docker run -d \
   --name=wg-easy \
-  -e LANG=de
+  -e LANG=de \
   -e WG_HOST=<b>🚨YOUR_SERVER_IP</b> \
   -e PASSWORD=<b>🚨YOUR_ADMIN_PASSWORD</b> \
   -v ~/.wg-easy:/etc/wireguard \