docs: add DOI badge to README

README.md

@@ -6,6 +6,7 @@
 [![downloads](https://img.shields.io/crates/d/zarrs)](https://crates.io/crates/zarrs)
 [![build](https://github.com/LDeakin/zarrs/actions/workflows/ci.yml/badge.svg)](https://github.com/LDeakin/zarrs/actions/workflows/ci.yml)
 [![codecov](https://codecov.io/gh/LDeakin/zarrs/graph/badge.svg?token=OBKJQNAZPP)](https://codecov.io/gh/LDeakin/zarrs)
+[![DOI](https://zenodo.org/badge/695021547.svg)](https://zenodo.org/badge/latestdoi/695021547)
 
 `zarrs` is a Rust library for the [Zarr](https://zarr.dev) storage format for multidimensional arrays and metadata. It supports [Zarr V3](https://zarr-specs.readthedocs.io/en/latest/v3/core/v3.0.html) and a [V3 compatible subset](https://docs.rs/zarrs/latest/zarrs/#implementation-status) of [Zarr V2](https://zarr-specs.readthedocs.io/en/latest/v2/v2.0.html).