twrpme: gigaset oem should be lowercase

Change-Id: I212f8793a4a9f89ff6f34b4647853994626443e0
diff --git a/_Gigaset/gigasetgs4.markdown b/_gigaset/gigasetgs4.markdown
similarity index 100%
rename from _Gigaset/gigasetgs4.markdown
rename to _gigaset/gigasetgs4.markdown