Examples: Fix broken links.

examples/webgl_materials_channels.html

@@ -10,7 +10,7 @@
 
 		<div id="info">
 			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - <span id="description">Normal, Depth, DepthRGBA, DepthRGBAUnpacked, Materials</span><br/>
-			by <a href="https://Clara.io">Ben Houston</a>. ninja head from <a href="http://developer.amd.com/tools-and-sdks/archive/legacy-cpu-gpu-tools/amd-gpu-meshmapper/" target="_blank" rel="noopener">AMD GPU MeshMapper</a>
+			by <a href="https://Clara.io">Ben Houston</a>. ninja head from <a href="https://gpuopen.com/archive/gamescgi/amd-gpu-meshmapper/" target="_blank" rel="noopener">AMD GPU MeshMapper</a>
 		</div>
 
 		<script type="module">

examples/webgl_materials_displacementmap.html

@@ -15,7 +15,7 @@
 
 		<div id="info">
 			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - (<span id="description">normal + ao + displacement + environment</span>) map demo.<br />
-			ninja head from <a href="http://developer.amd.com/tools-and-sdks/archive/legacy-cpu-gpu-tools/amd-gpu-meshmapper/" target="_blank" rel="noopener">AMD GPU MeshMapper</a>
+			ninja head from <a href="https://gpuopen.com/archive/gamescgi/amd-gpu-meshmapper/" target="_blank" rel="noopener">AMD GPU MeshMapper</a>
 
 			<div id="vt">displacement mapping requires vertex textures</div>
 		</div>