Add Zenodo DOIs (#238)

Author: gdalle

DifferentiationInterface/README.md

@@ -5,6 +5,7 @@
 [![Build Status](https://github.com/gdalle/DifferentiationInterface.jl/actions/workflows/CI.yml/badge.svg?branch=main)](https://github.com/gdalle/DifferentiationInterface.jl/actions/workflows/CI.yml?query=branch%3Amain)
 [![Coverage](https://codecov.io/gh/gdalle/DifferentiationInterface.jl/branch/main/graph/badge.svg)](https://app.codecov.io/gh/gdalle/DifferentiationInterface.jl)
 [![Code Style: Blue](https://img.shields.io/badge/code%20style-blue-4495d1.svg)](https://github.com/invenia/BlueStyle)
+[![DOI](https://zenodo.org/badge/740973714.svg)](https://zenodo.org/doi/10.5281/zenodo.11092033)
 
 |           Package            |                                                                                                                                                    Docs                                                                                                                                                    |
 | :--------------------------: | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |

DifferentiationInterfaceTest/README.md

@@ -3,6 +3,7 @@
 [![Build Status](https://github.com/gdalle/DifferentiationInterface.jl/actions/workflows/CI.yml/badge.svg?branch=main)](https://github.com/gdalle/DifferentiationInterface.jl/actions/workflows/CI.yml?query=branch%3Amain)
 [![Coverage](https://codecov.io/gh/gdalle/DifferentiationInterface.jl/branch/main/graph/badge.svg)](https://app.codecov.io/gh/gdalle/DifferentiationInterface.jl)
 [![Code Style: Blue](https://img.shields.io/badge/code%20style-blue-4495d1.svg)](https://github.com/invenia/BlueStyle)
+[![DOI](https://zenodo.org/badge/740973714.svg)](https://zenodo.org/doi/10.5281/zenodo.11092033)
 
 |           Package            |                                                                                                                                                    Docs                                                                                                                                                    |
 | :--------------------------: | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |