fix: typo error in CONTRIBUTING.md

[vivekBoii]

sorry but I dont know to do cahnges in two files and make PR
Hope you understand
New to open Source
practise -> practice

• Tests written, or not not needed

[AndyScherzinger]

No worries @vivekBoii all good and thanks again for your contribution.

For adding several changes on several files you would need to create a branch on git commit all changes you like to do to da that branch and when done, create a PR based on that branch. Hope this helps 😊

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