ci: add gitlab actions instead of travis CI

feat: add `graphql-compose@^8.0.0` to peer dependencies and update ot…

…her dependencies

chore: update dependencies

feat: allow to pass SchemaComposer's type instances without wrapping …

…them in functions

test: disable E2E tests temporary

feat: add `schemaComposer` option to `composeWithJson(typeName, json,…

… options)`

refactor: migrate from Flow to TypeScript

BREAKING CHANGE: Flowtype definitions were removed

chore: fix flow config

fix: for arrays of objects, use all fields when calculating types

feat: add support for nested arrays of objects

* Add support for nested arrays of objects

* Fix `yarn test` emitting syntax errors locally

(Due to babel transforms not being applied)

* Use a better type name for nested array members

* Update tests