Use parcel temperature

Use parcel temperature (parcel_profile) instead of environmental
temperature (temperature) for parcel_mixing_ratio derivation.

This makes a difference if you have a very high temperature point in the
stratosphere.

src/metpy/calc/thermo.py

@@ -2672,7 +2672,7 @@ def cape_cin(pressure, temperature, dewpoint, parcel_profile, which_lfc='bottom'
     # The mixing ratio of the parcel comes from the dewpoint below the LCL, is saturated
     # based on the temperature above the LCL
     parcel_mixing_ratio = np.where(below_lcl, saturation_mixing_ratio(pressure, dewpoint),
-                                   saturation_mixing_ratio(pressure, temperature))
+                                   saturation_mixing_ratio(pressure, parcel_profile))
 
     # Convert the temperature/parcel profile to virtual temperature
     temperature = virtual_temperature_from_dewpoint(pressure, temperature, dewpoint)