fix(ci): add leading slash to upstream/downstream project path
fix(ci): add leading slash to upstream/downstream project path

Related to CAM-13589
camunda/camunda-bpm-platform,langfr/camunda-bpm-platform,camunda/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,camunda/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,camunda/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,langfr/camunda-bpm-platform,camunda/camunda-bpm-platform,camunda/camunda-bpm-platform