build: import slf4j-api

smsb-customer-manager-client/pom.xml

@@ -20,7 +20,10 @@
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <scope>compile</scope>
-            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
         </dependency>
         <!-- cola -->
         <dependency>