Release v1.4.0 - Upgrade dependencies

What's Changed

• Upgrade some of the test dependencies by @tgharold in #29
• Add the README.md file to the NuGet package by @tgharold in #30
• Upgrade packages to latest versions by @tgharold in #31
• Pull the README.md for 'pack' from right spot by @tgharold in #32
• Switch to symlink for README.md by @tgharold in #33

Full Changelog: v1.3.1...v1.4.0