cryptography < 3.5:
You can skip the rust installation and other related dependencies by adding the line below before apk add commands:
ENV CRYPTOGRAPHY_DONT_BUILD_RUST=1
cryptography >= 3.5: Thanks @riptusk331
After this version rust will be required. Either install a specific version <3.5 or follow cryptography installation instructions. It is stated in the attached link that they are very aggressively explained in the docs.