Clean up SLF4J dependency

Author: kwin

pom.xml

@@ -73,17 +73,11 @@
       <version>6.0.0</version>
       <scope>provided</scope>
     </dependency>
-    <dependency>
-      <groupId>org.slf4j</groupId>
-      <artifactId>slf4j-api</artifactId>
-      <version>1.7.20</version>
-      <scope>provided</scope>
-    </dependency>
     <!-- TEST -->
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-simple</artifactId>
-      <version>1.7.20</version>
+      <version>1.7.25</version>
       <scope>test</scope>
     </dependency>
     <dependency>