release: Zephyr 2.0.0-rc1

Bump to 2.0.0-rc1.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
diff --git a/VERSION b/VERSION
index cf1f4dd..c359e4c 100644
--- a/VERSION
+++ b/VERSION
@@ -1,5 +1,5 @@
-VERSION_MAJOR = 1
-VERSION_MINOR = 14
-PATCHLEVEL = 99
+VERSION_MAJOR = 2
+VERSION_MINOR = 0
+PATCHLEVEL = 0
 VERSION_TWEAK = 0
-EXTRAVERSION =
+EXTRAVERSION = rc1