Publish using Java14 makes artifacts unusable on Java11

* What went wrong:
A problem occurred configuring root project 'cash'.
> Could not resolve all artifacts for configuration ':classpath'.
   > Could not resolve com.squareup.sqldelight:gradle-plugin:1.5.0-benoit03.
     Required by:
         project :
      > No matching variant of com.squareup.sqldelight:gradle-plugin:1.5.0-benoit03 was found. The consumer was configured to find a runtime of a library compatible with Java 11, packaged as a jar, and its dependencies declared externally but:
          - Variant 'apiElements' capability com.squareup.sqldelight:gradle-plugin:1.5.0-benoit03 declares a library, packaged as a jar, and its dependencies declared externally:
              - Incompatible because this component declares an API of a component compatible with Java 14 and the consumer needed a runtime of a component compatible with Java 11
          - Variant 'runtimeElements' capability com.squareup.sqldelight:gradle-plugin:1.5.0-benoit03 declares a runtime of a library, packaged as a jar, and its dependencies declared externally:
              - Incompatible because this component declares a component compatible with Java 14 and the consumer needed a component compatible with Java 11

[3flex]

if (plugins.hasPlugin("org.jetbrains.kotlin.jvm")) doesn’t work as intended - because the root project’s allprojects block is evaluated before the subprojects’ build scripts, hasPlugin(...) is always false because the plugin hasn’t been applied in the subproject yet.

The block should be changed to:

  plugins.withId("org.jetbrains.kotlin.jvm") {
    sourceCompatibility = JavaVersion.VERSION_1_8
    targetCompatibility = JavaVersion.VERSION_1_8
  }

I don’t know if this actually helps the original issue, which I experienced too but couldn’t find the root cause of - but just as an FYI.

[JakeWharton]

Good catch! Want to send a PR for that?