Enable publishing of incremental builds

[basil]

The intended use case of this is to be able to more easily test PR builds of this repository in realistic use cases, albeit with the additional effort of adding a custom <repository>.

Testing done

Compared the differential between the partially flattened (new) https://repo.jenkins-ci.org/incrementals/org/jenkins-ci/plugins/plugin/4.50-rc1383.e2d11257662a/plugin-4.50-rc1383.e2d11257662a.pom and the unflattened (old) https://repo.jenkins-ci.org/public/org/jenkins-ci/plugins/plugin/4.49/plugin-4.49.pom and did not see anything of concern. I encourage reviewers to look at this differential for themselves. The only changes seem to be that properties seem to be in a random order (probably going through some HashMap internally somewhere) and the elements of the POM have been re-ordered according to the POM Code Convention (which we could re-order in the main branch if we wanted to reduce the diff even further).

Verified that I could successfully consume the resulting incremental build in Text Finder plugin by running mvn clean verify -DskipTests with

diff --git a/pom.xml b/pom.xml
index 9e32894..e7acdfc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <parent>
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>plugin</artifactId>
-        <version>4.49</version>
+        <version>4.50-rc1383.e2d11257662a</version>
         <relativePath />
     </parent>
 
@@ -104,6 +104,13 @@
             <id>repo.jenkins-ci.org</id>
             <url>https://repo.jenkins-ci.org/public/</url>
         </repository>
+        <repository>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+            <id>incrementals</id>
+            <url>https://repo.jenkins-ci.org/incrementals/</url>
+        </repository>
     </repositories>
 
     <pluginRepositories>

[jglick]

See #462. I was nervous about enabling JEP-305 on this repo, but mainly it just needed testing.

[jglick]

@basil other than the merge conflict, is there anything holding this back?

[basil]

Just additional testing and hesitance to move forward with this given your intent to subsequently enable JEP-229 (which I prefer to avoid).

[jglick]

hesitance to move forward with this given your intent to subsequently enable JEP-229

That is an independent consideration. Enabling JEP-229 would simply be a subsuming PR. If you would block that, then I would not bother filing it to begin with.

[basil]

I would not block it, but ultimately it is a maintainer decision so I think it should be made by whoever is most actively maintaining the repository.