tm-bench: add deprecation warning (#3992)

- Added a deprecation warining in for deprecation of tm-bench in favor of tm-load-test

- With the merging of this pr we can close tm-bench related issues.

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

tools/tm-bench/README.md

@@ -1,4 +1,8 @@
-# tm-bench
+# tm-bench (Deprecated)
+
+> ## **Deprecation Warning**
+
+### This tool will be depreacted in favor of [tm-load-test](https://github.com/interchainio/tm-load-test).
 
 Tendermint blockchain benchmarking tool: