Added TemperatureChangeRate unit relation (#1371)

Added unit relation to get TemperatureChangeRate from TemperatureDelta
divided by Duration.

---------

Co-authored-by: Andreas Gullberg Larsen <[email protected]>

Author: Tim-Borcherding

UnitsNet.Tests/CustomCode/TemperatureDeltaTests.cs

@@ -64,5 +64,19 @@ public void TemperatureDeltaTimesEntropyEqualsEnergy()
             Energy energy = TemperatureDelta.FromKelvins(20) * Entropy.FromJoulesPerKelvin(4);
             Assert.Equal(Energy.FromJoules(80), energy);
         }
+
+        [Fact]
+        public void TemperatureDeltaDividedByTimeSpanEqualsTemperatureChangeRate()
+        {
+            TemperatureChangeRate changeRate = TemperatureDelta.FromKelvins(20) / TimeSpan.FromSeconds(2);
+            Assert.Equal(TemperatureChangeRate.FromDegreesCelsiusPerSecond(10), changeRate);
+        }
+
+        [Fact]
+        public void TemperatureDeltaDividedByDurationEqualsTemperatureChangeRate()
+        {
+            TemperatureChangeRate changeRate = TemperatureDelta.FromKelvins(20) / Duration.FromSeconds(2);
+            Assert.Equal(TemperatureChangeRate.FromDegreesCelsiusPerSecond(10), changeRate);
+        }
     }
 }