WIP: Update sbt to version 1.7.1

[LeeTibbert]

Update sbt to version 1.7.1 in two places.

That version has been released for 3 weeks. I have been using it for 10 to 14 days, on Linux & macOS (m1) without problems.

Caveat

On macOS there is a possible issue with how the sbt used to run scala is downloaded and installed.

Full description of sbt macOS install issue.

Short description -- if sdkman is used, sbt 1.71. works fine. If "brew" is used, the JDK version is forced to not-Java8

I would like to ensure that sdkman is used to download the 'outer' sbt runner before promoting this work to a PR.

Work in Progress

I am submitting this as a Work In Progress (WIP) because, mea culpa, I could not find how to change the version used by GitHub Actions. I studied the various .github & *-setup-env files. Does it require action from the person/people behind the curtain?

Since there appears to be on Single Point of Truth, it would be nice to document, at least in this PR, all the places which need to change in order to update the sbt version.

I am aware, and hope that the current CI proves out, that there is no requirement for the version of sbt used to launch the testing environment is the same as the one used in that environment (build.properties). However, maintaining parity makes the build easier to trace and reduces both the cognitive barrier and the need for hard-to-transmit-and-keep-alive lore.

Is the trick something in or below the login directory ~ of the account used to run CI? ~/.sbt and/or ~/.coursier? Keeps weenies like me out ;-)