Update lamem_input.dat

Some smart person had added the  PhaseTransition infrastructure along with a keyword to activate it, but did not add this to the master file.
As a result, this was not taken into account in the `LaMEM.jl` package as well and I spend hours looking for the bug...

input_models/input/lamem_input.dat

@@ -352,7 +352,8 @@
     useTk           = 1              # switch to use T-dependent conductivity, 0: not active
     dikeHeat        = 1		 # switch to use Behn & Ito heat source in the dike
     Compute_velocity_gradient = 1    # compute the velocity gradient tensor 1: active, 0: not active. If active, it automatically activates the output in the .pvd file
-
+    Phasetrans      = 0              # take phase transitions on particles into account (see  <PhaseTransitionStart>/ <PhaseTransitionEnd> below)
+
 # Groundwater level type specification:
 
 # gw_level_type = none  # don't compute pore pressure (default)