Fix gradle plugin badge

* Add sbt plugin integration test

* Suggestions from eed3si9n and test fixes

* Make schemasRootDir optional

* Update dependencies #112

* Update gradle configuration as per latest Gradle 6.3 #112

* Migrate from CircleCI to GitHub Actions #115

* Move codecov to a separate job, disable jdk 11,13 for a moment #115

* Fix caching actions #115

* Reorder tasks, add badge #115

Support both .graphqls and .graphql

Add extensions-related properties to Maven/Gradle plugins #81

The intermediate getter for schema paths is now public so that it can be part of the inputs.
This way, whether the schemas are found via explicit paths or SchemaFinder or the default config doesn't matter,
changes are picked up no matter what.

Resolves:
https://github.com/kobylynskyi/graphql-java-codegen/issues/83Co-authored-by: NJoffrey Bion <joffrey.bion@booking.com>

* Support extensions for all GraphQL types #81

* Performance improvement: scan definitions/extensions once #86

* Remove redundant methods from MapperUtils #86

* Fix plugin class names: Graphql -> GraphQL #86

* Fix test class name: GraphQLCodegenExtendTest #86

* Delete GraphqlCodegenExtendTest.java

* Fix mainClassName in gradle examples

* Add example of GraphQL mutation request #75

* Fix CI config