v0.3.1 🚀

Changes

• Fix warnings on Elixir v1.11 about missing apps @josevalim (#152)

🧰 Maintenance

• Tweak CI @princemaple (#153)
• Bump swoosh from 1.0.4 to 1.0.5 @dependabot (#151)
• Bump credo from 1.4.0 to 1.4.1 @dependabot (#149)
• Bump swoosh from 1.0.3 to 1.0.4 @dependabot (#150)
• Bump phoenix from 1.5.4 to 1.5.5 @dependabot (#148)
• Bump swoosh from 1.0.2 to 1.0.3 @dependabot (#147)
• Bump ex_doc from 0.22.5 to 0.22.6 @dependabot (#146)