chore: improve copilot instructions

Author: Barbapapazes

.github/copilot-instructions.md

@@ -5,3 +5,9 @@ In case of linting issue, try to run the following command:
 ```bash
 npm run lint:fix
 ```
+
+You can update the test snapshots by running:
+
+```bash
+npm run test -- -u --run
+```