Updates GcfJarLayout to write back classic loaders required for the current implementation of this project, before this change the default loaders would be used every time GcfJarLayout was invoked; also updates the pom for function-sample-gcp-http to use the latest development version of the spring cloud gcp adaptor

Fixes gh-1085

Author: lauren-wiebenga-s360

spring-cloud-function-adapters/spring-cloud-function-adapter-gcp/src/main/java/org/springframework/cloud/function/adapter/gcp/layout/GcfJarLayout.java

@@ -21,6 +21,7 @@
 import org.springframework.boot.loader.tools.CustomLoaderLayout;
 import org.springframework.boot.loader.tools.Layouts;
 import org.springframework.boot.loader.tools.LoaderClassesWriter;
+import org.springframework.boot.loader.tools.LoaderImplementation;
 import org.springframework.cloud.function.adapter.gcp.GcfJarLauncher;
 
 /**
@@ -46,7 +47,7 @@ public boolean isExecutable() {
 
 	@Override
 	public void writeLoadedClasses(LoaderClassesWriter writer) throws IOException {
-		writer.writeLoaderClasses();
+		writer.writeLoaderClasses(LoaderImplementation.CLASSIC);
 
 		String jarName = LAUNCHER_NAME.replaceAll("\\.", "/") + ".class";
 		writer.writeEntry(

spring-cloud-function-samples/function-sample-gcp-http/pom.xml

@@ -27,7 +27,7 @@
 		<dependency>
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-function-adapter-gcp</artifactId>
-			<version>4.1.0-SNAPSHOT</version>
+			<version>${spring-cloud-function.version}</version>
 		</dependency>
 
 		<!-- test dependencies -->