Added surface area calculation for pyramid

[wmathias00]

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

[wmathias00]

Added surface area calculation for pyramid.

[codecov-commenter]

Codecov Report

:x: Patch coverage is 0% with 7 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 77.93%. Comparing base (873dd97) to head (db6cdd6). :warning: Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/main/java/com/thealgorithms/maths/Area.java	0.00%	7 Missing :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6891      +/-   ##
============================================
- Coverage     77.96%   77.93%   -0.04%     
  Complexity     6431     6431              
============================================
  Files           736      736              
  Lines         21476    21483       +7     
  Branches       4204     4205       +1     
============================================
- Hits          16744    16742       -2     
- Misses         4060     4068       +8     
- Partials        672      673       +1     

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