Update lib/private/Preview/SVG.php

Co-authored-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>
Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

Author: susnux

lib/private/Preview/SVG.php

@@ -89,7 +89,7 @@ protected function canBeProcessed(string $content): bool {
 		// Strip all non-printable/control characters except newlines/tabs
 		$content = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/', '', $content);
 		// check for any potential external reference (include custom namespace prefix)
-		if (preg_match('/["\s\']([a-z_][a-z0-9_.]*:)?href\s*=/i', $content)) {
+		if (preg_match('/["\s\']([a-z_][a-z0-9_.-]*:)?href\s*=/i', $content)) {
 			return false;
 		}
 		return true;