grpc-app sample does not build

[Lipen]

Description

The sample project samples/grpc-app fails to build due to missing grpc plugin-settings-block (I am not sure how to call it):

rpc {
    grpc {  // <== Unresolved reference: grpc
        enabled = true
    }
}

Gradle log

> Configure project :
e: file:///.../kotlinx-rpc/samples/grpc-app/build.gradle.kts:31:5: Unresolved reference: grpc
e: file:///.../kotlinx-rpc/samples/grpc-app/build.gradle.kts:32:9: Unresolved reference: enabled

FAILURE: Build failed with an exception.

* Where:
Build file '.../kotlinx-rpc/samples/grpc-app/build.gradle.kts' line: 31

* What went wrong:
Script compilation errors:

  Line 31:     grpc {
               ^ Unresolved reference: grpc

  Line 32:         enabled = true
                   ^ Unresolved reference: enabled

2 errors

This can be "fixed" by using id("org.jetbrains.kotlinx.rpc.plugin") version "0.5.1-grpc-16" plugin version instead of 0.6.0 for this particular sample project. Seems like the plugin version was bumped to 0.6.0 in https://github.com/Kotlin/kotlinx-rpc/pull/320. However, kotlinx-rpc project does not include samples/* in the build (I even had to open this sample project in a separate IDEA, since it didn't load correctly in the root one), so the CI didn't caught that this sample does not build with 0.6.0 plugin anymore.

To Reproduce

1. Open samples/grpc-app as IDEA project.
2. Try to load the Gradle configuration or build the project
3. Error: Unresolved reference: grpc

Expected behavior

• All sample projects should run as they are, out of the box.
• All samples probably should be included in the root project.
• All samples should be tested on CI.
• All samples should be promptly updated to the latest kotlinx-rpc plugin version (0.7.0 at that time) on each release, and all major changes in the user API (like customization via rpc {} block) should be mentioned in the CHANGELOG.md.