v2.9.0

There are some major technical upgrades in this release, but no functional changes/breakage.

Most notably:

• Upgrade to the AWS SDK V2
• Rework the flag/config handling to allow OS env as flags, flags defined in config file and env var interpolation in config file. See the Documentation for more info.
• A set of integration tests using testscript has pulled the test coverage up around ~80%.
• We have ported the release script to Hugoreleaser. This means that the archive names have changed (standardised), but it also means that you get only one unviversal, notarized MacOS PKG archive.

Changes

• readme: Adjust cache value in example 2bac7ad @bep #52
• deps: go get -u 2b0aec3 @bep
• Update README.md b6d05c2 @bep
• Rework and simplify the flag/config handling 44c92f6 @bep #23
• Add integration tests d41c57c @bep
• Upgrade to aws-sdk-go-v2 1617a92 @bep