fix: Remove the outdated test jar import

Author: MichaelsJP

reader-gtfs/pom.xml

@@ -52,13 +52,6 @@
             <artifactId>logback-classic</artifactId>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>com.github.GIScience.graphhopper</groupId>
-            <artifactId>graphhopper-core</artifactId>
-            <version>4.9-SNAPSHOT</version>
-            <type>test-jar</type>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.hamcrest</groupId>
             <artifactId>hamcrest-library</artifactId>