Change Renode version from 1.13.3 to 1.15.3

Author: WojMel

README.md

@@ -108,7 +108,7 @@ The [release](.github/workflows/release.yml) workflow contains an example usage
 
 ## Emulation
 
-The Linux emulation runs on the RISC-V HiFive Unleashed single core platform in [Renode 1.13.3](https://github.com/renode/renode). Basic specs like 8GB of RAM and a network connection are configured in the emulated system.
+The Linux emulation runs on the RISC-V HiFive Unleashed single core platform in [Renode 1.15.3](https://github.com/renode/renode). Basic specs like 8GB of RAM and a network connection are configured in the emulated system.
 
 ### Architecture
 

action.yml

@@ -105,7 +105,7 @@ runs:
         sudo pip3 install -r requirements.txt
       shell: bash
       env:
-        RENODE_VERSION: "1.13.3"
+        RENODE_VERSION: "1.15.3"
 
     - id: create-pip-virtual-environment
       run: cd ${GITHUB_ACTION_PATH} && mkdir -p venv-dir && python3 -m venv venv-dir