GH-731 Add support for SDK CloudEvent type

The type itself comes form cloud event sdk. And while s-c-function provides native support for cloud events, this is necessary for cases when user uses CloudEvent type in the signature of a function

Resolves #731

spring-cloud-function-deployer/src/it/simplestjar/pom.xml

@@ -25,8 +25,30 @@
 					<target>1.8</target>
 				</configuration>
 			</plugin>
+			<plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.2.4</version>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
 		</plugins>
 	</build>
+	
+	<dependencies>
+		<dependency>
+		    <groupId>io.cloudevents</groupId>
+		    <artifactId>cloudevents-api</artifactId>
+		    <version>2.2.0</version>
+		    <optional>true</optional>
+		</dependency>
+	</dependencies>
 
 
 </project>

spring-cloud-function-deployer/src/it/simplestjar/src/main/java/function/example/EchoCloudEventFunction.java

@@ -0,0 +1,16 @@
+package function.example;
+
+import java.util.Map;
+import java.util.function.Function;
+
+import io.cloudevents.CloudEvent;
+
+public class EchoCloudEventFunction implements Function<CloudEvent, CloudEvent> {
+
+	@Override
+	public CloudEvent apply(CloudEvent value) {
+		System.out.println("Received " + value);
+		return value;
+	}
+
+}

spring-cloud-function-deployer/src/it/simplestjar/src/main/java/function/example/UpperCaseFunction.java

@@ -1,13 +0,0 @@
-package function.example;
-
-import java.util.function.Function;
-
-public class UpperCaseFunction implements Function<String, String> {
-
-	@Override
-	public String apply(String value) {
-		System.out.println("Uppercasing " + value);
-		return value.toUpperCase();
-	}
-
-}