Added memoization function in fibonacci

[JDeepD]

Describe your change:

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[andrei-polukhin]

Looks very well overall, just fix one comment.
Edit: forgot one moment, see the latest review

[andrei-polukhin]

Everything is fine

[andrei-polukhin]

@JDeepD Looks well for me, ask for review people with write access to repo such as @Kush1101 and @cclauss

[cclauss]

Please use the same tests as the other implementations. Please put the test results in the docstring at the top of the file so that visitors can see at a glance how these algorithms perform.

[JDeepD]

Please use the same tests as the other implementations.

Like, should I output a list of n fibonacci numbers??

[cclauss]

The doctests should be the same for all functions to ensure they all deliver the right answers.

Like run the file and paste in the text that the last four lines generate.

[cclauss]

Nice performance numbers! Thanks for the teamwork on this one.