Fix username input type

closes codecentric#1307

Author: joshiste

spring-boot-admin-server-ui/src/main/frontend/login.html

@@ -52,7 +52,7 @@ <h1 class="title has-text-primary" th:text="${uiSettings.title}">Spring Boot Adm
  </div>
  <div class="field">
  <div class="control">
- <input class="input is-medium" type="input" name="username" placeholder="Username"
+ <input class="input is-medium" type="text" name="username" placeholder="Username"
  data-i18n="placeholder:login.placeholder.username" autofocus th:classappend="${param.error != null} ? is-danger">
  </div>
  </div>