Using n as a parameter in the function pattern, where n>0, complete the codes to get the
pattern (take the help of examples):
Note: There is no newline in the end (after the pattern ends)
pattern(3) should return "1\n1*2\n1**3", e.g. the following:
1
1*2
1**3
pattern(10): should return the following:
1
1*2
1**3
1***4
1****5
1*****6
1******7
1*******8
1********9
1*********10