utils/spdx: add support for complex expressions

.github/workflows/spdx.yml

Library/Homebrew/config.rb

Library/Homebrew/data/spdx/spdx_exceptions.json

Library/Homebrew/data/spdx/spdx_licenses.json

Library/Homebrew/dev-cmd/update-license-data.rb

Library/Homebrew/test/support/lib/config.rb

Library/Homebrew/test/utils/spdx_spec.rb

Library/Homebrew/utils/spdx.rb