Revert "config: version: ShiftOS 5.1"

This reverts commit 254fad35f6640a037b7754d7755be8430587a692.

Reason: Keep 5.0 for now and bump before new G release to keep
        L at 5.0 as well.

Change-Id: I6e9a49f0db55bbfe0cd8b5ce90c6a4f0bde0aafd
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>
diff --git a/config/version.mk b/config/version.mk
index c512fa1..96e6b69 100644
--- a/config/version.mk
+++ b/config/version.mk
@@ -9,7 +9,7 @@
 ####################################################################################
 
 SHIFT_SOS_VERSION_MAJOR := 5
-SHIFT_SOS_VERSION_MINOR := 1
+SHIFT_SOS_VERSION_MINOR := 0
 SHIFT_SOS_VERSION_EXTRA :=
 
 ifeq ($(SHIFT_BUILD_WITH_GMS),true)