add regex to key input

pass/views/login/key.ejs

@@ -10,7 +10,7 @@
       </h3>
       <form id="key-form" action="<%= baseDir _%>/key/enter" method="post" enctype="multipart/form-data">
         <input type="password" name="key" id="key" placeholder="<%=
-        req.t("key-input.placeholder", {ns: "login"}) _%>" autofocus />
+        req.t("key-input.placeholder", {ns: "login"}) _%>" autofocus pattern="([0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}|[0-9a-z]{6})" />
       </form>
     </div>
     <div id="file-option" class="enter-option">