simple contacts: fixing hal icon

Author: quentinll

publications/simple-contact-solver/index.html

@@ -109,7 +109,7 @@ <h1 class="title is-1 publication-title">From Compliant to Rigid Contact Simulat
                 <a href="https://hal.science/hal-04588906"
                    class="external-link button is-normal is-rounded is-dark">
                   <span class="icon">
-                    <i class="fa-solid fa-square-h"></i>
+                    <i class="fas fa-square-h"></i>
                   </span>
                   <span>HAL</span>
                 </a>