Change interval units to milliseconds

Allow the monitoring intervals to be specified in
milliseconds instead of seconds in order to handle
polling intervals less than a second.

Change-Id: I3ef078df29ef2866920f00103710b02dbde6fcb2
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/power-sequencer/main.cpp b/power-sequencer/main.cpp
index 923b5dc..87b8070 100644
--- a/power-sequencer/main.cpp
+++ b/power-sequencer/main.cpp
@@ -43,7 +43,7 @@
         exit(EXIT_FAILURE);
     }
 
-    std::chrono::seconds interval{i};
+    std::chrono::milliseconds interval{i};
 
     sd_event* e = nullptr;
     auto r = sd_event_default(&e);