Adopt GHA Scala Library Release Workflow

This is the second library, after https://github.com/guardian/etag-caching, to adopt
https://github.com/guardian/gha-scala-library-release-workflow/blob/main/README.md .

The changes required to adopt the automated workflow:

* No need to set `sonatypeProfileName` or `ThisBuild / publishTo`,
  that's now done by the workflow.
* Remove the sign, publish, release & push steps of sbt-release's `releaseProcess`
  configuration, because the workflow does those now, and the workflow only
  wants `sbt release` to create the versioning commits, and tag them appropriately.
  The workflow does the rest itself.
* Remove `sbt-pgp` plugin because it's no longer used - the workflow does the signing
  using `gpg` directly.

Additionally, we add **automatic version numbering** based on compatibility assessment
performed by `sbt-version-policy`:

* Add the `sbt-version-policy` plugin, to allow it to do the compatibility assessment.
  This also sets the `versionScheme` for this library to `early-semver`, which is
  the recommended versioning for Scala libraries, and `sbt-version-policy` and
  correct sbt-eviction-issue-detection pretty much depend on the `versionScheme`
  being `early-semver`. Thus we also need to switch to using a new semver version
  number for our library version!
* Add the `releaseVersion := fromAggregatedAssessedCompatibilityWithLatestRelease().value`
  sbt setting, which will intelligently set the release version based on `sbt-version-policy`'s
  compatibility assessment, thanks to scalacenter/sbt-version-policy#187 .
* Use `publish / skip := true`, rather than other hacks like `publish := {}` or
  `publishArtifact := false`, to tell sbt not to publish modules that we don't want published
  (typically, the 'root' module) - this is important because `sbt-version-policy` won't
  understand those hacks, but _will_ understand `publish / skip := true` means that it doesn't
  need to assess compatibility there.

Author: rtyley

build.sbt

@@ -1,4 +1,5 @@
-import ReleaseTransformations._
+import ReleaseTransformations.*
+import sbtversionpolicy.withsbtrelease.ReleaseVersion.fromAggregatedAssessedCompatibilityWithLatestRelease
 
 lazy val baseSettings = Seq(
   scalaVersion := "2.13.11",
@@ -86,9 +87,8 @@ lazy val `play-secret-rotation-root` = (project in file("."))
     `aws-parameterstore-lambda`
   )
   .settings(baseSettings).settings(
-  publishArtifact := false,
-  publish := {},
-  publishLocal := {},
+  publish / skip := true,
+  releaseVersion := fromAggregatedAssessedCompatibilityWithLatestRelease().value,
   releaseCrossBuild := true, // true if you cross-build the project for multiple Scala versions
   releaseProcess := Seq[ReleaseStep](
     checkSnapshotDependencies,
@@ -98,11 +98,7 @@ lazy val `play-secret-rotation-root` = (project in file("."))
     setReleaseVersion,
     commitReleaseVersion,
     tagRelease,
-    // For non cross-build projects, use releaseStepCommand("publishSigned")
-    releaseStepCommandAndRemaining("+publishSigned"),
-    releaseStepCommand("sonatypeBundleRelease"),
     setNextVersion,
-    commitNextVersion,
-    pushChanges
+    commitNextVersion
   )
 )

project/plugins.sbt

@@ -1,6 +1,6 @@
-addSbtPlugin("com.github.sbt" % "sbt-release" % "1.1.0")
+addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "3.1.0")
 
-addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.2.1")
+addSbtPlugin("com.github.sbt" % "sbt-release" % "1.1.0")
 
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.9.21")
 

sonatype.sbt

@@ -1,7 +1,3 @@
-sonatypeProfileName := "com.gu"
-
-ThisBuild / publishTo := sonatypePublishToBundle.value
-
 ThisBuild / scmInfo := Some(ScmInfo(
   url("https://github.com/guardian/play-secret-rotation"),
   "scm:git:[email protected]:guardian/play-secret-rotation.git"

version.sbt

@@ -1 +1 @@
-ThisBuild / version := "0.41-SNAPSHOT"
+ThisBuild / version := "1.0.0-SNAPSHOT"