Create Maximum depth of the bt.java

[CHALLARIDURGAPRASAD]

Describe your change:

I seen in this repository there is algorithm about the maximum height of the binary tree. I added an algorithm which will calculate maximum height of the tree and it is the one of the best algorithm which will take less time complexity and as well as space complexity.

• [x] Add an algorithm?

References

Checklist:

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized.
• [x] I know that pull requests will not be merged if they fail the automated tests.
• [x] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [ ] All new Java files are placed inside an existing directory.
• [ ] All filenames are in all uppercase characters with no spaces or dashes.
• [ ] All functions and variable names follow Java naming conventions.
• [ ] 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}.