AppDaemon Log showing lots of : FutureWarning: The behavior of array concatenation with empty entries is deprecated

[swests]

Describe the bug
AppDaemon Log showing lots of : "FutureWarning: The behavior of array concatenation with empty entries is deprecated" warnings

HA: 2024.7.4
PV_Opt: 3.15.4

To Reproduce
Steps to reproduce the behavior:

1. Start AppDaemon
2. Goto the the AppDaemon log

Expected behavior
No errors/warnings

Screenshots
From AppDaemon Log:

/homeassistant/appdaemon/apps/pv_opt/pv_opt.py:2175: FutureWarning: The behavior of array concatenation with empty entries is deprecated. In a future version, this will no longer exclude empty items when determining the result dtype. To retain the old behavior, exclude the empty entries before the concat operation.
  cost = pd.DataFrame(pd.concat([cost_today, cost])).set_axis(["cost"], axis=1).fillna(0)

Additional context
It's a warning for now, but one for the backlog?

[fboundy]

Yes - should be an easy enough thing to fix.