Remove the unsupported Nodes GraphQL library

[mc1arke]

The library that had been used to integrate with GitHub's GraphQL APIs is no longer maintained. As the rest of the project uses Rest APIs to integrate with services, there's a fairly mature GitHub Java library, and switching to any other GraphQL library is likely to require as much effort as switching to a Rest implementation, this change is removing the GraphQL implementation and moving to the github-api library bundled within Sonarqube. As GitHub's Rest API does not support minimising comments, old summary comments are being deleted rather than minimised after a new summary comment is added. Additionally, the 'bridging' features used in the github-api library cause issues when mockito attempts to mock/spy a bridged class, so an unbridged version of the library has been specified at the start of the test runtime classpath to allow unit testing using the affected classes.

Includes an upgrade to the docker-compose file to use a newer Postgres version and resolve some linting issues.

[mc1arke]

This will fix #969

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
98.5% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud