Depend on the released Doxia 1.12.0, not the snapshot

[slachiewicz]

This branch's build fails before it compiles anything:

[ERROR] Failed to execute goal on project maven-reporting-impl: Could not resolve dependencies
[ERROR] dependency: org.apache.maven.doxia:doxia-sink-api:jar:1.12.0-SNAPSHOT (compile)
[ERROR]   Could not find artifact org.apache.maven.doxia:doxia-sink-api:jar:1.12.0-SNAPSHOT in Nexus

doxiaVersion is still 1.12.0-SNAPSHOT. That snapshot is long gone from the snapshot repository, and 1.12.0 was released — so this is just dropping the suffix. It is the only -SNAPSHOT dependency in the POM; the project's own 3.3.0-SNAPSHOT version is untouched.

dependency:resolve succeeds afterwards, picking up doxia-sink-api, doxia-core and doxia-logging-api at 1.12.0 alongside the sitetools artifacts already pinned at 1.11.1.

I could not run a full build locally — the branch targets Java 7 and my JDK is too new (Source option 7 is no longer supported); CI builds it on JDK 8/11/17. Dependency resolution is the part that was failing and it is what I verified.

Heads-up for the next build: this branch is also on parent maven-shared-components 34, whose apache-rat 0.13 rejects the .mvn/wrapper/maven-wrapper.properties that the Jenkins shared library now generates. Once resolution is fixed, the build will most likely reach the RAT check and fail there. apache/maven-reporting-api#77 is the same fix for the sibling repository. Context in apache/maven#12676.

[github-actions]

@slachiewicz The PR can't be associated to a milestone, because there are multiple open milestones. Please add the text "branch: maven-reporting-impl-3.x" to the description to the milestone where this PR belongs to.