Update spray json version to 1.3.5 due to 3rd party vulnerability issues CVE-2018-18853, CVE-2018-18854

Current Situation

• Currently JobScheduler Master uses spray-json_2.11 version 1.3.3
• Two vulnerabilities affect this version,
  • see https://nvd.nist.gov/vuln/detail/CVE-2018-18853
  • see https://nvd.nist.gov/vuln/detail/CVE-2018-18854

Desired Behavior

• Due to the vulnerability Issue of the spray-json_2.11 and the bug-fixes provided with current releases the JobScheduler Master should use the current version 1.3.5.