Update index.html

Trying to shorten the URL because on Netlify it just redirects to github page

Author: devutkarshdixit

index.html

@@ -632,8 +632,7 @@ <h2 class="title">Contact Me</h2>
                     <div class="text">Message me</div>
                     <form action="https://formsubmit.co/utkarshdixit2021@gmail.com" method="post" enctype="multipart/form-data"> 
                         <input type="hidden" name="_captcha" value="false">
-                        <input type="hidden" name="_next"
-                            value="https://devutkarshdixit.github.io/thanku.html">
+                        <input type="hidden" name="_next" value="./thanku.html">
                         <input type="hidden" name="_autoresponse"
                             value="Thank-You for submitting this form, I shall be contacting you soon, from your given details!">