Issue #5479 : added volume of Frustum Cone function in src/main/java/com/thealgorithms/maths/Volume.java and assert function for the same in src/test/java/com/thealgorithms/maths/Volume.java

Issue #5479 : added volume of Frustum Cone function in src/main/java/com/thealgorithms/maths/Volume.java and assert function for the same in src/test/java/com/thealgorithms/maths/Volume.java #1971