Silence the pkl-gradle pom metadata warning

[HuzaifaChaudary]

Closes #1743

the warning

every publish of pkl-gradle prints:

> Task :pkl-gradle:generatePomFileForPluginMavenPublication
Maven publication 'pluginMaven' pom metadata warnings (silence with 'suppressPomMetadataWarningsFor(variant)'):
  - Variant runtimeElements:
      -  contains dependencies that cannot be represented in a published pom file.
          - dependency on project ':pkl-tools' declared with Gradle attributes

it comes from the deliberate declaration in pkl-gradle.gradle.kts:

runtimeOnly(projects.pklTools) {
  attributes { attribute(Bundling.BUNDLING_ATTRIBUTE, objects.named(Bundling.SHADOWED)) }
}

a pom has no way to express a variant attribute, so gradle warns that it is dropping one.

why silencing is the right answer here rather than papering over

i checked what is actually lost before suppressing anything.

the pom still declares the dependency. it is not missing, only the variant selection is:

<dependency>
  <groupId>org.pkl-lang</groupId>
  <artifactId>pkl-tools</artifactId>
  <version>0.33.0-SNAPSHOT</version>
  <scope>runtime</scope>
</dependency>

the module metadata keeps the attribute:

variant runtimeElements -> pkl-tools attributes: {'org.gradle.dependency.bundling': 'shadowed'}

and only gradle consumes a gradle plugin. the warning itself says the module file is unaffected, and that is the file gradle reads. there is no maven build resolving pkl-gradle as a library, so the pom limitation has no consumer to hurt.

so the information gradle is warning about is genuinely not needed by anyone who consumes this artifact, which is the case suppressPomMetadataWarningsFor exists for.

verification

check	result
warning before	present
warning after	gone
generated pom before vs after	byte identical
module metadata after	still carries bundling: shadowed

the diff is ten lines in one file and changes nothing that gets published.

built and verified against main at 1208fa9 with the repo's own gradle toolchain, jdk 25.0.2.

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disclaimer: this contribution was prepared with the assistance of an ai agent. i reproduced the warning first, diffed the generated pom to confirm the published artifact is unchanged, and checked the module metadata myself before opening this.