Added Vulert into README.md

[ankitdn]

Added Vulert into README.md

[mre]

Hello @ankitdn,

thanks for your contribution.

The tool looks great, however the README.md file is auto-generated from the files in data/tools. Can you please go ahead and create a new YAML file in that directory with the information for the tool? You can take a look at the existing files to get an idea of the file format.
The README.md will be rendered automatically then, so the manual changes can be reverted.

See https://github.com/analysis-tools-dev/static-analysis/blob/master/CONTRIBUTING.md and the other merged pull requests.