tachsensor: Fix 'Associations' capitalization to register associations

Before patch:
```
# busctl introspect xyz.openbmc_project.FanSensor /xyz/openbmc_project/inventory/Fan1_0 xyz.openbmc_project.Association.Definitions
NAME                                        TYPE      SIGNATURE RESULT/VALUE                             FLAGS
.associations                               property  a(sss)    1 "sensors" "inventory" "/xyz/openbmc... emits-change

# busctl tree xyz.openbmc_project.ObjectMapper | grep Fan1_0
    | | |- /xyz/openbmc_project/sensors/fan_tach/Fan1_0
    | | | `- /xyz/openbmc_project/sensors/fan_tach/Fan1_0/chassis
```

After patch:
```
# busctl introspect xyz.openbmc_project.FanSensor /xyz/openbmc_project/inventory/Fan1_0 xyz.openbmc_project.Association.Definitions
NAME                                        TYPE      SIGNATURE RESULT/VALUE                             FLAGS
.Associations                               property  a(sss)    1 "sensors" "inventory" "/xyz/openbmc... emits-change

# busctl tree xyz.openbmc_project.ObjectMapper | grep Fan1_0
    | |- /xyz/openbmc_project/inventory/Fan1_0
    | | `- /xyz/openbmc_project/inventory/Fan1_0/sensors
    | | |- /xyz/openbmc_project/sensors/fan_tach/Fan1_0
    | | | |- /xyz/openbmc_project/sensors/fan_tach/Fan1_0/chassis
    | | | `- /xyz/openbmc_project/sensors/fan_tach/Fan1_0/inventory

```

Change-Id: Ie7fd69a4dc7216fb2dcfb1fdccc2b7885c7511ee
Signed-off-by: Glukhov Mikhail <mikl@greenfil.ru>
diff --git a/src/TachSensor.cpp b/src/TachSensor.cpp
index cd9a892..7c026b8 100644
--- a/src/TachSensor.cpp
+++ b/src/TachSensor.cpp
@@ -85,7 +85,7 @@
         itemAssoc = objectServer.add_interface(
             "/xyz/openbmc_project/inventory/" + name, association::interface);
         itemAssoc->register_property(
-            "associations",
+            "Associations",
             std::vector<Association>{
                 {"sensors", "inventory",
                  "/xyz/openbmc_project/sensors/fan_tach/" + name}});