Update installation instructions in README.md

[sruti1312]

Signed-off-by: Sruti Parthiban partsrut@amazon.com

Is your feature request related to a problem? Please provide an existing Issue # , or describe. https://github.com/opensearch-project/perftop/issues/18

Describe the solution you are proposing Updating the installation instruction in README. Instructions will point to the release page that holds the executables, which can be used to install perftop, until perftop is added to npm.

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature request here.

Check List

• [x] New functionality includes testing.
  • [ ] All tests pass
• [ ] New functionality has been documented.
  • [ ] New functionality has javadoc added
• [x] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[stockholmux]

Thanks @sruti1312 for the quick turn on this!