Update README.md - Add small information for better understanding. Especially for Windows users.

[KingAlex1985]

Some small information added for better understanding. Especially for Windows users.

Fix # (see https://help.github.com/en/articles/closing-issues-using-keywords)

Describe changes proposed in this pull request:

• no (java) code changes, only added smal information for README.md

Checks

• The commit log is comprehensible. It follows 7 rules of great commit messages. We can fix this during merge by using a squash+merge if necessary
• Has tests or has a separate issue that describes the types of test that should be created. If no test is included it should explicitly be mentioned in the PR why there is no test.
• Is this PR adding logic based on one or more clinical attributes? If yes, please make sure validation for this attribute is also present in the data validation / data loading layers (in backend repo) and documented in File-Formats Clinical data section!
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[KingAlex1985]

@zainasir
I have done some small updates at the readme file. Maybe you can check / review this?
Thank you in advance.
AlexK