test: add missing implementation-plan test targets

tests/integration_test/examples_basic_e2e_build_test.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+build_file="$1"
+readme_file="$2"
+
+[[ -f "${build_file}" ]]
+[[ -f "${readme_file}" ]]
+grep -Eq '^package\(default_visibility = \["//visibility:public"\]\)$' "${build_file}"