space icon-links evenly across (pydata#1726)

* space icon-links evenly across pydata#1720

(rather than justified left)

* restore column-gap

Author: leifwalsh

src/pydata_sphinx_theme/assets/styles/components/_icon-links.scss

@@ -7,6 +7,7 @@
   flex-direction: row;
   column-gap: 1rem;
   flex-wrap: wrap;
+  justify-content: space-evenly;
 
   // Remove the padding so that we can define it with flexbox gap above
   li.nav-item a.nav-link {