Explicitly cast double values down to float in Row.GetFloat().

Supports casting to float in Pomelo.EntityFramworkCore.MySql for MySQL < 8.0.17.

Signed-off-by: Laurents Meyer <laucomm@gmail.com>

Author: lauxjpn

src/MySqlConnector/Core/Row.cs

@@ -353,7 +353,8 @@ public double GetDouble(int ordinal)
 		public float GetFloat(int ordinal)
 		{
 			var value = GetValue(ordinal);
-			return value is decimal decimalValue ? (float) decimalValue :
+			return value is double doubleValue ? (float) doubleValue :
+				value is decimal decimalValue ? (float) decimalValue :
 				(float) value;
 		}