release: bump version to 3.7.1-rc1

Bump version to 3.7.1-rc1

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/VERSION b/VERSION
index f1fc2eb..1b2e10c 100644
--- a/VERSION
+++ b/VERSION
@@ -1,5 +1,5 @@
 VERSION_MAJOR = 3
 VERSION_MINOR = 7
-PATCHLEVEL = 0
+PATCHLEVEL = 1
 VERSION_TWEAK = 0
-EXTRAVERSION =
+EXTRAVERSION = rc1