Update the version to 1.21 in preparation for a new release.

PiperOrigin-RevId: 241053616

CMakeLists.txt

@@ -3,6 +3,7 @@
 # found in the LICENSE file. See the AUTHORS file for names of contributors.
 
 cmake_minimum_required(VERSION 3.9)
+# Keep the version below in sync with the one in db.h
 project(leveldb VERSION 1.21.0 LANGUAGES C CXX)
 
 # This project can use C11, but will gracefully decay down to C89.

include/leveldb/db.h

@@ -13,9 +13,9 @@
 
 namespace leveldb {
 
-// Update Makefile if you change these
+// Update CMakeLists.txt if you change these
 static const int kMajorVersion = 1;
-static const int kMinorVersion = 20;
+static const int kMinorVersion = 21;
 
 struct Options;
 struct ReadOptions;