[BEAM-6726] remove duplicate artifact declaration on maven publish

[adude3141]

This fixes improper configuration in :beam-sdks-java-bom as to not add duplicated artefact declaration.

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Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	Gearpump	Samza	Spark
Go		---	---	---	---	---	---
Java
Python		---			---	---	---

See .test-infra/jenkins/README for trigger phrase, status and link of all Jenkins jobs.

[adude3141]

R: @aaltay

[aaltay]

Run Java PreCommit

[aaltay]

Do you know why tests are failing?

[adude3141]

See corresponding thread
http://mail-archives.apache.org/mod_mbox/beam-dev/201902.mbox/%3cCALsTK6+pQzcuCUj9Yx1y4b6FchRm8XYhRao86MxiXje_xQJsAA@mail.gmail.com%3e

[aaltay]

OK, let's wait for that issue to be resolved.

[kennknowles]

Green.

[kennknowles]

I have a question - how can we make this failure happen in our continuous build so it is caught before release time?

[kennknowles]

Is it just that we have to eliminate the isRelease flag and do all the same things during snapshot releases? The things controlled by -PisRelease, -Ppublishing and -PnoSigning seem like they could be controlled by choosing different gradle targets. WDYT?

[aaltay]

I am all for removing all those flags from our build. It does not make sense to me that we have pieces of build code that is only tested at release times.

If that is not feasible (gradle experts to confirm) I would at least suggest having a nightly job to run release process exactly as we ask a release manager to do. Literally a script to follow the release guide.

[adude3141]

+1 for moving as much as possible to our automated (daily) snapshot builds, e.g. https://builds.apache.org/job/beam_Release_NightlySnapshot/

Unfortunately I m not to familiar with beams publish/release process and all these flags. Ideally only difference would be the SNAPSHOT appendix on version (and with that the target repo)

Need to look deeper into this.