exclude slf4j-nop from geopackage to avoid SLF4J warning (#874)

planetiler-core/pom.xml

@@ -153,6 +153,12 @@
       <groupId>mil.nga.geopackage</groupId>
       <artifactId>geopackage</artifactId>
       <version>${geopackage.version}</version>
+      <exclusions>
+      <exclusion>
+        <groupId>org.slf4j</groupId>
+        <artifactId>slf4j-nop</artifactId>
+      </exclusion>
+    </exclusions>
     </dependency>
   </dependencies>