Update README.md

README.md

@@ -19,6 +19,7 @@
 * [About the Project](#about-the-project)
   * [Documentation](#documentation)
   * [Built with](#built-with)
+  * [Download](#download)
 * [Usage](#usage)
   * [Validity ranges](#validity-ranges)
 * [License](#license)
@@ -53,6 +54,10 @@ The current release of the proton response files is based on:
 * Ray-tracing Monte Carlo code [Mineo et al., Exp. Astr., 44, 287, 2017]
 * ATHENA WFI and X-IFU Geant4 mass models provided by the ATHENA Instrument Consortia (2022 design)
 
+### Download
+
+Official releases of the response files can be downloaded [here](https://www.ict.inaf.it/gitlab/proton_response_matrix/athena-proton-response-files/-/releases).
+
 
 <!-- USAGE -->
 ## Usage