Added Dijkstra's Algorithm in Greedy Algorithms

[foxxmg]

• [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

❌ Patch coverage is 0% with 34 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.16%. Comparing base (3c70a54) to head (23ee708).

Files with missing lines	Patch %	Lines
...a/com/thealgorithms/greedyalgorithms/Dijkstra.java	0.00%	28 Missing ⚠️
...n/java/com/thealgorithms/maths/HarmonicNumber.java	0.00%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6975      +/-   ##
============================================
- Coverage     78.28%   78.16%   -0.13%     
  Complexity     6581     6581              
============================================
  Files           744      746       +2     
  Lines         21910    21944      +34     
  Branches       4293     4298       +5     
============================================
  Hits          17153    17153              
- Misses         4074     4108      +34     
  Partials        683      683              

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