schemas: virtual sensor: Add Minimum for calculation sensor uses

Minimum has been implemented in phosphor-virtual-sensors [1]. This
commit supports Minimum type in schemas.

[1] https://gerrit.openbmc.org/c/openbmc/phosphor-virtual-sensor/+/74099

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I2370c22c487caaaaaf812b6b91024d82c96388fb
diff --git a/schemas/virtual_sensor.json b/schemas/virtual_sensor.json
index 512ea85..c9ba378 100644
--- a/schemas/virtual_sensor.json
+++ b/schemas/virtual_sensor.json
@@ -39,7 +39,7 @@
                 "Type": {
                     "description": "The type of calculation this sensor uses.",
                     "type": "string",
-                    "enum": ["ModifiedMedian", "Maximum"]
+                    "enum": ["Maximum", "Minimum", "ModifiedMedian"]
                 },
                 "Units": {
                     "description": "The sensor type, as it shows up in the D-Bus object name.",