Update plugin publish to v0.21.0 (#3362)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

gradle/libs.versions.toml

@@ -88,7 +88,7 @@ kotlin-js = { id = "org.jetbrains.kotlin.js", version.ref = "kotlin" }
 dokka = { id = "org.jetbrains.dokka", version.ref = "dokka" }
 intellij = { id = "org.jetbrains.intellij", version = "1.6.0" }
 grammarKitComposer = { id = "com.alecstrong.grammar.kit.composer", version = "0.1.10" }
-publish = { id = "com.vanniktech.maven.publish", version = "0.20.0" }
+publish = { id = "com.vanniktech.maven.publish", version = "0.21.0" }
 spotless = { id = "com.diffplug.spotless", version = "6.7.2" } # When updating, check if we can remove base plugin from root build.gradle
 changelog = { id = "org.jetbrains.changelog", version = "1.3.1" }
 shadow = { id = "com.github.johnrengelman.shadow", version = "7.1.2" }