schema: Add virtual sensor schema

This schema allows entity manager to define virtual sensors that are
used by the virtual-sensor daemon from the phosphor-virtual-sensor
repository.

Currently only a modified median of sensor values is accepted by
phosphor-virtual-sensor.

Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I510dbcd843f703073a96ad33cfe748d0dcd21e64
diff --git a/meson.build b/meson.build
index 357ada1..4302724 100644
--- a/meson.build
+++ b/meson.build
@@ -148,6 +148,7 @@
     'Pid.json',
     'Pid.Zone.json',
     'Stepwise.json',
+    'VirtualSensor.json',
 ]
 
 foreach s : schemas