version mistake in build.gradle file

[DanielCWeston]

At https://developer.android.com/codelabs/android-proto-datastore#4

protobuf {
    protoc {
        artifact = "com.google.protobuf:protoc:21.7"
    }

Should be

protobuf {
    protoc {
        artifact = "com.google.protobuf:protoc:3.21.7"
    }