Update link to test resource in readme

Co-authored-by: Johannes Visintini <[email protected]>

README.md

@@ -59,7 +59,7 @@ To run the tests locally, you need the following:
     * -Dport.get starts data-aggregation + metadata tests using GET requests
     * -Dport.post starts data-aggregation tests using POST requests
     * -Dport.data starts data-extraction tests using GET and POST requests
-2. [heidelberg.oshb](https://downloads.ohsome.org/v0.5/europe/germany/baden-wuerttemberg/heidelberg_68900_2020-07-23.oshdb.mv.db) file (or any other, which includes the data from Heidelberg)
+2. [heidelberg.oshdb](https://downloads.ohsome.org/v0.6/europe/germany/baden-wuerttemberg/heidelberg_68900_2020-07-23.oshdb.mv.db) file (or any other, which includes the data from Heidelberg)
 3. maven command: `mvn -Dport_get=8081 -Dport_post=8082 -Dport_data=8083 -DdbFilePathProperty="--database.db=<path-to-your-heidelberg.oshdb-file>" test`
 
 *Note:* 
@@ -166,4 +166,3 @@ DOCS_DEPLOYMENT=release make clean html
 ## License
 
 [AGPL](LICENSE).
-