chore: add GG-Plugin-Class to manifest (#71)

Author: MikeDombo

pom.xml

@@ -79,6 +79,18 @@
             </resource>
         </resources>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.3.0</version>
+                <configuration>
+                    <archive>
+                        <manifestEntries>
+                            <GG-Plugin-Class>com.aws.greengrass.secretmanager.SecretManagerService</GG-Plugin-Class>
+                        </manifestEntries>
+                    </archive>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>