Added Go Mod Support

Added Go Mod Support

• Updated makefile
• Updated awslabs references in code
• Added GH Actions build
• Removed CircleCI build
• Removed old Gopkg files

v0.3.1

• Resolved issue where proxy response headers were not being passed through
• Resolved issue where query parameters were duplicated, e.g ?name=value was passed erroneously through as ?name=value?name=value
• Added additional make build targets for dev_setup, format, lint
• Leveraged deps dependency management