update minor version for 6.11 release (#6994)

Summary:
The 6.11.fb branch is already cut so I will also backport this PR to
that branch.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6994

Reviewed By: riversand963

Differential Revision: D22084532

Pulled By: ajkr

fbshipit-source-id: 0b025f738cc31c65c673cbf89302359e88a34d19

include/rocksdb/version.h

@@ -5,7 +5,7 @@
 #pragma once
 
 #define ROCKSDB_MAJOR 6
-#define ROCKSDB_MINOR 10
+#define ROCKSDB_MINOR 11
 #define ROCKSDB_PATCH 0
 
 // Do not use these. We made the mistake of declaring macros starting with