Sign release files instead of archive subset

[jkasten2]

Description

One Line Summary

Fixes missing .asc signing files when uploading to Sonatype to ship a release to Maven Central.

Details

Motivation

Without this change Sonatype reject the release and you can't ship a release.

Scope

Only effects signing for releases.

Gradle Documentation

See Gradle's Maven Publish Plugin documentation and its complete example on how publishing.publications is used.

Testing

Manual testing

Tested this by uploading a release to Sonatype and confirmed it passes it's validation after closing and all .asc files exist. Also created a 4.6.4-rc1 release to ensure it works end-to-end with Maven Central.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes
• Release Signing

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
• I have reviewed this PR myself, ensuring it meets each checklist item

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This change is 

[jkasten2]

Tests failed due to one unrelated flaky test.

com.test.onesignal.GenerateNotificationRunner > shouldContainPayloadWhenOldSummaryNotificationIsOpened FAILED
    junit.framework.ComparisonFailure: expected:<UUID[2]> but was:<UUID[1]>
        at junit.framework.Assert.assertEquals(Assert.java:100)
        at junit.framework.Assert.assertEquals(Assert.java:107)
        at com.test.onesignal.GenerateNotificationRunner.shouldContainPayloadWhenOldSummaryNotificationIsOpened(GenerateNotificationRunner.java:345)