mesalib: Update version from 18.2.1 to 18.2.3

Release notes:

1.  https://www.mesa3d.org/relnotes/18.2.2.html
2.  https://www.mesa3d.org/relnotes/18.2.3.html

mesalib.be0

@@ -1,6 +1,6 @@
 #!/usr/bin/env beesh
 
-# BEE_VERSION mesalib-18.2.1-0
+# BEE_VERSION mesalib-18.2.3-0
 
 ## 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.)