Add requirement for minimum bash version for running unit tests

Author: prateekgogia

contributors/devel/development.md

@@ -322,6 +322,10 @@ this permanent, add this to your `.bashrc` or login script:
 export PATH="$GOPATH/src/k8s.io/kubernetes/third_party/etcd:${PATH}"
 ```
 
+##### BASH version requirement
+
+To successfully run unit tests in Kubernetes, you will need bash version installed to be >4.3.
+
 Once you have installed all required software, you can proceed to the
 [Building Kubernetes](#building-kubernetes) section to test if it all works properly.