java_gapic_assembly_gradle_pkg rule does not generate javadocs task in client build.gradle #1367

Environment details

• Programming language: Java

Steps to reproduce

I use bazel to build a java_gapic_assembly_gradle_pkg rule to build a java client library tar:

java_gapic_assembly_gradle_pkg(
    name = "API-v1-java",
    include_samples = True,
    transport = "grpc+rest",
    deps = [
        ":FOO_java_gapic",
        ":FOO_java_grpc",
        ":FOO_java_proto",
        ":FOO_proto",
    ],
)

When java_gapic_assembly_gradle_pkg is used to generate a java client library tar, if you run ./gradlew build from the top-level directory of the extracted tar, it will generate javadocs for proto and grpc, but not for the gapic client

Expected behavior:

When I run ./gradlew build from the top level directory of the extracted tar generated by the java_gapic_assembly_gradle_pkg rule, these javadocs should be generated:

API-v1-java/gapic-API-v1-java/build/docs/javadoc
API-v1-java/grpc-API-v1-java/build/docs/javadoc
API-v1-java/proto-API-v1-java/build/docs/javadoc

Actual behavior:

Only the grpc and proto javadocs are generated, but not the gapic javadocs

Suggested Fix

https://github.com/googleapis/rules_gapic/blob/main/java/resources/gradle/client.gradle.tmpl

https://github.com/googleapis/rules_gapic/blob/main/java/resources/gradle/client_disco.gradle.tmpl

It looks like these are templates that are used by the java_gapic_assembly_gradle_pkg rule to generate the build.gradle file for the gapic client, and they do not contain a task for generating javadocs.

By contrast, the gradle template files for proto and grpc do:

https://github.com/googleapis/rules_gapic/blob/main/java/resources/gradle/proto.gradle.tmpl

https://github.com/googleapis/rules_gapic/blob/main/java/resources/gradle/grpc.gradle.tmpl

Could add this to https://github.com/googleapis/rules_gapic/blob/main/java/resources/gradle/client.gradle.tmpl and https://github.com/googleapis/rules_gapic/blob/main/java/resources/gradle/client_disco.gradle.tmpl

task javadocJar(type: Jar) {
  classifier = 'javadoc'
  from javadoc
}

artifacts {
  archives javadocJar
}