Updated freq_str in plot_spectrogram() as 's' of pd.Timedelta is now …

…preferred over 'S'

Signed-off-by: S.J. Guillot <58807831+sjg2203@users.noreply.github.com>

yasa/plotting.py

@@ -331,7 +331,7 @@ def plot_spectrogram(
 
     if hypno is not None:
         # Convert sampling frequency to pandas timefrequency string (e.g., "30s")
-        freq_str = pd.tseries.frequencies.to_offset(pd.Timedelta(1 / sf, "S")).freqstr
+        freq_str = pd.tseries.frequencies.to_offset(pd.Timedelta(1 / sf, "s")).freqstr
         # Create Hypnogram instance for plotting
         hyp = Hypnogram(hypno_int_to_str(hypno), freq=freq_str)
         hypnoplot_kwargs = dict(lw=1.5, fill_color=None)