readme UPDATE mention crypt dependency

Refs #464

Author: michalvasko

README.md

@@ -61,6 +61,7 @@ the `distro` directory.
 
 * C compiler (gcc >= 4.8.4, clang >= 3.0, ...)
 * cmake >= 3.5.0
+* crypt(3)
 * [libyang](https://github.com/CESNET/libyang)
 * libssh >= 0.9.5 (for SSH support)
 * OpenSSL >= 3.0.0 (for TLS support)