Added bare CentOS 7 install dependencies

Author: cpiker

README.md

@@ -34,8 +34,10 @@ build libdas2.3:
 Though package names vary from system to system, commands for installing the
 prequisites are provided below \.\.\.
 ```bash
-$ sudo yum install expat-devel fftw-devel openssl-devel             # RedHat 7 and similar
-$ sudo apt install libexpat-dev libfftw3-dev libssl-dev zlib1g-dev  # Debian 9 and similar
+$ sudo yum install expat-devel fftw-devel openssl-devel # CentOS 7 and similar
+$ sudo yum install python3-devel python36-numpy         # CentOS 7 and similar
+
+$ sudo apt install libexpat-dev libfftw3-dev libssl-dev zlib1g-dev    # Debian 9 and similar
 ```
 and on windows using [vcpkg](https://github.com/microsoft/vcpkg)\.\.\.
 ```batchfile