Add DOI badge

Author: dstansby

README.md

@@ -1,5 +1,7 @@
 # Zarr benchmarks for 3D images
 
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.17806390.svg)](https://doi.org/10.5281/zenodo.17806390)
+
 This repository contains benchmarks for creating, reading, and storing huge 3D
 images in [Zarr](https://zarr.dev/) arrays. It was done as part of the
 [HEFTIE project](https://github.com/HEFTIEProject).

docs/index.md

@@ -11,6 +11,7 @@ which are presented below.
 
 These benchmarks are part of the wider
 [HEFTIE project](https://github.com/HEFTIEProject).
+The current version can be cited from zenodo: [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.17806390.svg)](https://doi.org/10.5281/zenodo.17806390)
 
 ## Executive summary