Issue #415 - add preact (#433)

* add preact icon

* fix reference index

* update preact official logo

Co-authored-by: Terence Eden <edent@users.noreply.github.com>

images/svg/preact.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+aria-label="Preact" role="img"
+viewBox="0 0 512 512"><rect
+width="512" height="512"
+rx="15%"
+fill="#fff"/><g transform="translate(256,256)"><path d="M0,-256 221.7025033688164,-128 221.7025033688164,128 0,256 -221.7025033688164,128 -221.7025033688164,-128z" fill="#673ab8"/><ellipse cx="0" cy="0" stroke-width="16px" rx="75px" ry="196px" fill="none" stroke="white" transform="rotate(52.5)"/><ellipse cx="0" cy="0" stroke-width="16px" rx="75px" ry="196px" fill="none" stroke="white" transform="rotate(-52.5)"/><circle cx="0" cy="0" r="34" fill="white"/></g></svg>