Use snap install yq in local_testnet (#6468)

* Use snap install yq in local_testnet

snap is better than apt since it's recommended in yq doc

scripts/local_testnet/README.md

@@ -9,7 +9,7 @@ This setup can be useful for testing and development.
 
 1. Install [Kurtosis](https://docs.kurtosis.com/install/). Verify that Kurtosis has been successfully installed by running `kurtosis version` which should display the version.
 
-1. Install [yq](https://github.com/mikefarah/yq). If you are on Ubuntu, you can install `yq` by running `sudo apt install yq -y`.
+1. Install [yq](https://github.com/mikefarah/yq). If you are on Ubuntu, you can install `yq` by running `snap install yq`.
 
 ## Starting the testnet
 
@@ -82,4 +82,4 @@ The script comes with some CLI options, which can be viewed with `./start_local_
 
 ```bash
 ./start_local_testnet.sh -b false
-```
+```