Added support information (PR #2457)

Author: vasudeva8

README.md

@@ -41,3 +41,9 @@ Please cite this paper when using BCFtools for your publications. http://samtool
     eprint = {https://academic.oup.com/gigascience/article-pdf/10/2/giab008/36332246/giab008.pdf},
 }
 ```
+
+### Support
+
+If you have found a bug or would like a new feature, please report the same in the GitHub [BCFtools](https://github.com/samtools/bcftools/issues) issue tracker.
+
+For any security related issue, please send a mail to [[email protected]](mailto:[email protected]) instead of reporting in the GitHub issue tracker.