Updates desktop client version to 2.5.1.

Signed-off-by: Camila San <hello@camila.codes>

VERSION.cmake

@@ -1,6 +1,6 @@
 set( MIRALL_VERSION_MAJOR 2 )
 set( MIRALL_VERSION_MINOR 5 )
-set( MIRALL_VERSION_PATCH 0 )
+set( MIRALL_VERSION_PATCH 1 )
 set( MIRALL_VERSION_YEAR  2018 )
 set( MIRALL_SOVERSION 0 )