Update copyright

Author: harrycodawang

_includes/footer.html

@@ -7,7 +7,7 @@ <h3>
           <img alt="" src="{{site.url}}/images/oms-white-logo.png" />
         </a>
       </h3>
-      <p>Copyright &copy; 2018 OpenMessaging Project, a Linux Foundation Collaborative Project. All Rights Reserved unless explicitly granted under an open source license.<br> The Linux Foundation is a registered trademark of The Linux Foundation. Linux is a registered trademark of Linus Torvalds.<br> Please see our <a href="https://www.linuxfoundation.org/terms" target="_blank">terms of use</a>, <a href="https://www.linuxfoundation.org/trademark-usage" target="_blank">trademark usage</a> and <a href=" https://www.linuxfoundation.org/privacy" target="_blank">privacy policy</a></p>
+      <p>Copyright &copy; 2017~2019 OpenMessaging Project, a Linux Foundation Collaborative Project. All Rights Reserved unless explicitly granted under an open source license.<br> The Linux Foundation is a registered trademark of The Linux Foundation. Linux is a registered trademark of Linus Torvalds.<br> Please see our <a href="https://www.linuxfoundation.org/terms" target="_blank">terms of use</a>, <a href="https://www.linuxfoundation.org/trademark-usage" target="_blank">trademark usage</a> and <a href=" https://www.linuxfoundation.org/privacy" target="_blank">privacy policy</a></p>
       <div class='spacing'></div>
       <div class='spacing'></div>
     </div>

images/@index/OpenMessaging.htm

@@ -566,7 +566,7 @@ <h3>
                     <img alt="" src="./OpenMessaging_files/oms-white-logo.png">
                 </a>
             </h3>
-            <p>Copyright © 2017 OpenMessaging Project, a Linux Foundation Collaborative Project. All Rights Reserved
+            <p>Copyright © 2017~2019 OpenMessaging Project, a Linux Foundation Collaborative Project. All Rights Reserved
                 unless explicitly granted under an open source license.<br> The Linux Foundation is a registered
                 trademark of The Linux Foundation. Linux is a registered trademark of Linus Torvalds.<br> Please see our
                 <a href="https://www.linuxfoundation.org/terms" target="_blank">terms of use</a>, <a