Compile opentelemetry-runtime-telemetry-java17 in Java 8 (#13393)

Author: jeanbisutti

instrumentation/runtime-telemetry/runtime-telemetry-java17/library/build.gradle.kts

@@ -57,4 +57,17 @@ tasks {
     dependsOn(testPS)
     dependsOn(testSerial)
   }
+
+  tasks {
+    compileJava {
+      // We compile this module for java 8 because it is used as a dependency in spring-boot-autoconfigure.
+      // If this module is compiled for java 17 then gradle can figure out based on the metadata that
+      // spring-boot-autoconfigure has a dependency that requires 17 and fails the build when it is used
+      // in a project that targets an earlier java version.
+      // https://github.com/open-telemetry/opentelemetry-java-instrumentation/issues/13384
+      sourceCompatibility = "1.8"
+      targetCompatibility = "1.8"
+      options.release.set(null as Int?)
+    }
+  }
 }