Publishing local plugin

Trying to make a plugin and publish it to local repo directory.
Plugin ./build.gradle.kts

plugins {
    kotlin("jvm") version "1.3.71"
    id("java-gradle-plugin")
    `maven-publish`

}

group = "com.abc"
version = "1.0.0"

repositories {
    mavenCentral()
}

dependencies {
    implementation(kotlin("stdlib-jdk8"))
}

gradlePlugin {
    plugins {
        create("playground") {
            id = "playground"
            implementationClass = "com.abc.PlaygroundPlugin"
        }
    }
}

tasks {
    compileKotlin {
        kotlinOptions.jvmTarget = "1.8"
    }
    compileTestKotlin {
        kotlinOptions.jvmTarget = "1.8"
    }
}

val sourcesJar by tasks.registering(Jar::class) {
    archiveClassifier.set("sources")
    from(sourceSets.main.get().allSource)
}

publishing {
    repositories {
        maven {
            url = uri("./repo")
        }
    }
    publications {
        register("mavenJava", MavenPublication::class) {
            from(components["kotlin"])
            artifact(sourcesJar.get())
        }
    }
}

And trying to use it ./demo/build.gradle.kts:

buildscript {
    repositories {
        maven {
            url = uri("../repo")
        }
    }

    dependencies {
        classpath("com.abc:playground:1.0.0")
    }
}
plugins {
    kotlin("jvm") version "1.3.71"
    id("playground") version "1.0.0"
}

group = "com.abc.demo"
version = "1.0-SNAPSHOT"

repositories {
    mavenCentral()
}

dependencies {
    implementation(kotlin("stdlib-jdk8"))
}

tasks {
    compileKotlin {
        kotlinOptions.jvmTarget = "1.8"
    }
    compileTestKotlin {
        kotlinOptions.jvmTarget = "1.8"
    }
}

The plugin is located correctly. But add it to plugins failes:
Plugin [id: 'playground', version: '1.0.0'] was not found in any of the following sources

Do I miss something?

Did you create a com.abc.demo.properties file in src/main/resources/META-INF/gradle-plugins/ containing implementation-class=com.abc.demo.PlaygroundPlugin? Please look up the details in the documentation.

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