mesalib: Update version from 18.1.6 to 18.2.1

Built with the command below.

    $ prun python python --version
    Python 2.7.15

configure: error: Python mako module v0.8.0 or higher not found

mesalib.be0

@@ -1,6 +1,6 @@
 #!/usr/bin/env beesh
 
-# BEE_VERSION mesalib-18.1.6-0
+# BEE_VERSION mesalib-18.2.1-0
 
 ## this file was created by bee init and should be executed to build a
 ## bee-package. (Additional hints are located at the end of this file.)