Sops-install-secrets: yaml: control characters are not allowed

[mschneiderwng]

sops-nix worked until I added more and larger entries like keys and certs in my secrets.yaml. Updating NixOS results in the error

/nix/store/45wk315grw281cdrs5y78k35nqsl13l9-sops-install-secrets-0.0.1/bin/sops-install-secrets: manifest is not valid: cannot parse yaml of ‘/nix/store/3240m3lisdb6blarz00238bqlcydjb3b2-source/secrets/secrets.yaml’: yaml: control characters are not allowed

May be related to https://stackoverflow.com/questions/33717799/go-yaml-control-characters-are-not-allowed-error