v1.6.0

FEATURES:

• New Resource linode_rdns

• New Data Resource linode_networking_ip

ENHANCEMENTS:

• Builds now use go mod
• provider: Support custom ua_prefix
• provider: Support custom API endpoint url

BUG FIXES:

• Documentation and examples for linode_domain resource were missing required type field
• linode_domain_record field ttl_sec accepts 0, as the API does (#35)
• linode_domain fields ttl_sec, retry_sec, expire_sec, and refresh_sec now accept 0, as the API does