Revert recommendation of `releasePublishArtifactsAction` for signing
Revert recommendation of `releasePublishArtifactsAction` for signing

Unfortunately this configuration (using `releasePublishArtifactsAction`),
doesn't work with multi-module projects - the setting does not appear to
take effect, the signing action is not taken, and the subsequent
`sonatypeReleaseAll` fails on closing the staging repository, eg:

```
[info] repositoryCloseFailed: id:commadgag-1154, cause:com.sonatype.nexus.staging.StagingRulesFailedException: One or more rules have failed
[error] Failed to close the repository
[error] Activity close started:2017-08-26T23:10:02.013Z, stopped:2017-08-26T23:10:13.267Z
[error]     Failed: signature-staging, failureMessage:Missing Signature: '/com/madgag/scala-git/scala-git_2.10/3.5/scala-git_2.10-3.5-javadoc.jar.asc' does not exist for 'scala-git_2.10-3.5-javadoc.jar'.
[error] java.lang.Exception: Failed to close the repository
[error] 	at xerial.sbt.Sonatype$NexusRESTService.closeStage(Sonatype.scala:721)
[error] 	at xerial.sbt.Sonatype$NexusRESTService.closeAndPromote(Sonatype.scala:820)
[error] 	at xerial.sbt.Sonatype$SonatypeCommand$.$anonfun$sonatypeReleaseAll$2(Sonatype.scala:215)
```

This problem was fixed for me by reverting to the old configuration,
see https://github.com/rtyley/scala-io/commit/fc82246b

xerial/sbt-sonatype