Increment version to 4.0.6.22.

Author: jamescowens

configure.ac

@@ -3,7 +3,7 @@ AC_PREREQ([2.60])
 define(_CLIENT_VERSION_MAJOR, 4)
 define(_CLIENT_VERSION_MINOR, 0)
 define(_CLIENT_VERSION_REVISION, 6)
-define(_CLIENT_VERSION_BUILD, 21)
+define(_CLIENT_VERSION_BUILD, 22)
 define(_CLIENT_VERSION_IS_RELEASE, false)
 define(_COPYRIGHT_YEAR, 2020)
 define(_COPYRIGHT_HOLDERS,[The %s developers])