Fix newsletter period wording

Author: leviem1

email/subscribe.html

@@ -8,7 +8,7 @@
         <div class="row justify-content-md-center text-center mb-5">
             <div class="col-lg-7">
                 <h1 class="title font-weight-normal mb-3">Subscribe to Our Newsletter</h1>
-                <p>Use the form below to sign up for our quarterly newsletter! We will never share your email address, and you can always unsubscribe <a href="/email/unsubscribe.html">here</a>.</p>
+                <p>Use the form below to sign up for our bi-annual newsletter! We will never share your email address, and you can always unsubscribe <a href="/email/unsubscribe.html">here</a>.</p>
             </div>
         </div>
         <div class="row justify-content-md-center">