Update version to 17.0.0-rc3

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/VERSION b/VERSION
index 032c50c..0b34163 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-17.0.0-rc2
+17.0.0-rc3