build: fix typo in release-docker script

Author: felixfbecker

release-docker.php

@@ -5,6 +5,6 @@
 $dockerPassword = getenv('DOCKER_PASSWORD');
 $version = json_decode(file_get_contents(__DIR__ . '/package.json'))->version;
 
-system("docker login -e=$dockerEmail -u=$dockerEmail -p=$dockerPassword");
+system("docker login -e=$dockerEmail -u=$dockerUsername -p=$dockerPassword");
 system("docker build -t felixfbecker/php-language-server:$version .");
 system("docker push felixfbecker/php-language-server:$version");