Change remote url of uGFX to relative path

diff --git a/lib/ugfx b/lib/ugfx
index 3e97b74e03c93631cdd3ddb2ce43b963fdce19b2..d108287cb10c3ec1c8e402b484e93c52b8cd7113 160000 (submodule)
--- a/lib/ugfx
+++ b/lib/ugfx
@@ -1 +1 @@
-Subproject commit 3e97b74e03c93631cdd3ddb2ce43b963fdce19b2
+Subproject commit d108287cb10c3ec1c8e402b484e93c52b8cd7113