Added new method to check Perfect Square

[TaranjeetSinghKalsi]

Added a new method to check Perfect Square using Pow() method. Also added test cases.

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized it.
• [x] All filenames are in PascalCase.
• [x] All functions and variable names follow Java naming conventions.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [x] All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 70.47%. Comparing base (95875b0) to head (03605bf).

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5917   +/-   ##
=========================================
  Coverage     70.47%   70.47%           
- Complexity     4808     4810    +2     
=========================================
  Files           642      642           
  Lines         17412    17414    +2     
  Branches       3351     3352    +1     
=========================================
+ Hits          12271    12273    +2     
  Misses         4680     4680           
  Partials        461      461           

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.