Avoid using relative paths

Author: stevebux

.github/actions/e2e-tests/action.yml

@@ -51,9 +51,9 @@ runs:
       if: steps.check_e2e.outputs.run_e2e == 'true'
       shell: bash
       run: |
-        echo "$APP_PEM_FILE" > internal-dev-test-1.pem
-        chmod 600 internal-dev-test-1.pem
+        echo "$APP_PEM_FILE" > "${GITHUB_WORKSPACE}/internal-dev-test-1.pem"
+        chmod 600 "${GITHUB_WORKSPACE}/internal-dev-test-1.pem"
         export PROXY_NAME=nhs-notify-supplier--internal-dev--nhs-notify-supplier
         export API_ENVIRONMENT=internal-dev
-        export NON_PROD_PRIVATE_KEY=internal-dev-test-1.pem
+        export NON_PROD_PRIVATE_KEY="${GITHUB_WORKSPACE}/internal-dev-test-1.pem"
         make .internal-dev-test