[release] Update version file for next release (2.5.0)

TBR=whesse@google.com

Change-Id: I1dfa130d8ff9c770eb6b6a9edf4fed32c3d9a9d9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107282
Reviewed-by: Alexander Thomas <athom@google.com>
diff --git a/tools/VERSION b/tools/VERSION
index 5b4d144..99fb67f 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -31,8 +31,8 @@
 #
 CHANNEL be
 MAJOR 2
-MINOR 3
-PATCH 3
+MINOR 5
+PATCH 0
 PRERELEASE 0
 PRERELEASE_PATCH 0
 ABI_VERSION 6