Bump IgluCore to 1.1.0

[istreeter]

This is related to snowplow/schema-ddl#117

We had accidentally made Iglu Server too strict when validating schemas. A schema with additional properties is technically usable by the Iglu System, but Iglu Server would refuse to accept the schema and would instead report an error.

After bumping IgluCore and SchemaDdl to latest versions, any additional property will be a warning, not an error. The warning is helpful, because it slightly protects from accidental typos in field names, but it does not prevent the schema from being accepted.