Migrate Avro message converter artifacts

Migrate Avro message converter (non-schema-registry) artifacts
from Spring Cloud Schema Registry to Spring Cloud Function.

Resolves https://github.com/spring-cloud/spring-cloud-function/issues/732
Resolves #733

spring-cloud-function-context/pom.xml

@@ -15,6 +15,10 @@
 		<version>3.2.0-SNAPSHOT</version>
 	</parent>
 
+	<properties>
+		<avro.version>1.10.2</avro.version>
+	</properties>
+
 	<dependencies>
 		<dependency>
 			<groupId>net.jodah</groupId>
@@ -86,6 +90,14 @@
 			<artifactId>kotlinx-coroutines-reactor</artifactId>
 			<optional>true</optional>
 		</dependency>
+
+		<!-- AVRO -->
+		<dependency>
+			<groupId>org.apache.avro</groupId>
+			<artifactId>avro</artifactId>
+			<version>${avro.version}</version>
+			<optional>true</optional>
+		</dependency>
 	</dependencies>
 	<build>
 		<plugins>
@@ -165,6 +177,24 @@
 					</execution>
 				</executions>
 			</plugin>
+			<plugin>
+				<groupId>org.apache.avro</groupId>
+				<artifactId>avro-maven-plugin</artifactId>
+				<version>${avro.version}</version>
+				<executions>
+					<execution>
+						<phase>generate-test-sources</phase>
+						<goals>
+							<goal>schema</goal>
+						</goals>
+						<configuration>
+							<outputDirectory>${project.basedir}/target/generated-test-sources</outputDirectory>
+							<testOutputDirectory>${project.basedir}/target/generated-test-sources</testOutputDirectory>
+							<testSourceDirectory>${project.basedir}/src/test/resources/avro</testSourceDirectory>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 </project>