Add pypi download badge

Author: jeromekelleher

README.md

@@ -1,4 +1,5 @@
 [![CI](https://github.com/sgkit-dev/vcztools/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/sgkit-dev/vcztools/actions/workflows/ci.yml)
+[![PyPI Downloads](https://static.pepy.tech/badge/vcztools)](https://pepy.tech/projects/vcztools)
 
 # vcztools
 Partial reimplementation of bcftools for [VCF Zarr](https://github.com/sgkit-dev/vcf-zarr-spec/)
@@ -17,24 +18,24 @@ python3 -m pip install vcztools
 ```
 vcztools view <path.vcz>
 ```
-or 
+or
 ```
 python -m vcztools view <path.vcz>
 ```
-should be equivalent to running 
+should be equivalent to running
 ```
 bcftools view <path.vcf.gz>
 ```
 
-See the [bio2zarr](https://sgkit-dev.github.io/bio2zarr/) project for help in 
+See the [bio2zarr](https://sgkit-dev.github.io/bio2zarr/) project for help in
 converting VCF files to Zarr.
 
 ## Goals
 
 Vcztools aims to be a drop-in replacement for a subset of bcftools functionality.
 Currently supported are the ``view``, ``query`` and ``index -s/-n`` commands.
 
-We aim for 100% compatibility so if you notice a difference between the output of 
+We aim for 100% compatibility so if you notice a difference between the output of
 vcztools and bcftools please do open an issue.
 
 ## Cloud stores
@@ -62,6 +63,6 @@ python -m vcztools view s3://<bucket-name>/path/to.vcz
 
 ## Development
 
-Vcztools is under active development and contributions are warmly welcomed. Please 
+Vcztools is under active development and contributions are warmly welcomed. Please
 see the project on [GitHub](https://github.com/sgkit-dev/vcztools).