docs: Upgrade Overpass fonts to 3.0

Since we are using Overpass for the web pages, we might be using the
latest version.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

docs/fonts/stylesheet.css

 @font-face {
 	font-family: 'LibvirtOverpass';
-	src: url('hinted-Overpass-Reg.woff') format('woff');
+	src: url('overpass-regular.woff') format('woff');
 	font-weight: normal;
 	font-style: normal;
 }
 
 @font-face {
 	font-family: 'LibvirtOverpass';
-	src: url('hinted-Overpass-Italic.woff') format('woff');
+	src: url('overpass-italic.woff') format('woff');
 	font-weight: normal;
 	font-style: italic;
 }
 
 @font-face {
 	font-family: 'LibvirtOverpass';
-	src: url('hinted-Overpass-Bold.woff') format('woff');
+	src: url('overpass-bold.woff') format('woff');
 	font-weight: bold;
 	font-style: normal;
 }
 
 @font-face {
 	font-family: 'LibvirtOverpass';
-	src: url('hinted-Overpass-BoldItalic.woff') format('woff');
+	src: url('overpass-bold-italic.woff') format('woff');
 	font-weight: bold;
 	font-style: italic;
 }
 
 @font-face {
 	font-family: 'LibvirtOverpassLight';
-	src: url('hinted-Overpass-Light.woff') format('woff');
+	src: url('overpass-light.woff') format('woff');
 	font-weight: 300;
 	font-style: normal;
 }
 
 @font-face {
 	font-family: 'LibvirtOverpassLight';
-	src: url('hinted-Overpass-LightItalic.woff') format('woff');
+	src: url('overpass-light-italic.woff') format('woff');
 	font-weight: 300;
 	font-style: italic;
 }