Add Volume "Algorithm Frustum Of Cone" Then Test It. (#5479)

* Add Function volumeFrustum To Calculate Frustum Of Cone Then Test It.

* Add Function volumeFrustumOfCone To Calculate Frustum Of Cone Then Test It.

* Update VolumeTest.java

* Update Volume.java

src/test/java/com/thealgorithms/maths/VolumeTest.java

@@ -32,5 +32,8 @@ public class VolumeTest {
 
         /* test pyramid */
         assertTrue(Volume.volumePyramid(10, 3) == 10.0);
+
+        /* test frustum */
+        assertTrue(Volume.volumeFrustumOfCone(3, 5, 7) == 359.188760060433);
     }
 }