0.0.3

CHANGES:

• Add constraint on fmt (@kit-ty-kate, #16)
• Be neutral when the DNS record does not give to us anything (@dinosaure, #17)
• Fix pp_mechanism for a and mx if no domain-spec are present (no :)
  (@hannesm, @dinosaure, #18)
• Update ocamlformat (@dinosaure, #19, #20)
• Use the last version of mirage-crypto-rng (@dinosaure, #20)
• Lint dependencies and remove the astring dependency (@dinosaure, #20)
• Update the documentation (@dinosaure, #20)
• Split the libraries according to schedulers (@dinosaure, #21)