Athenz v1.11.8 Release

What's Changed

• include optional attestation data string for ssh cert requests by @havetisyan in #1950
• move aws document validation into a utils class by @havetisyan in #1951
• In athenz-auth-core skip tests for arm architecture by @OferLevi85 in #1952
• auto purge expired role/group members based on server/domain config by @mendi160 in #1941

Full Changelog: v1.11.7...v1.11.8