resolves #382 don't run test suite for docs changes
- don't run tests and linter when branch begins with docs/
- don't run tests and linter otherwise unless code was changed
- extract defs to top of file in GitLab CI config
- use merge operator to weave defs into job definitions in GitLab CI config
- upgrade container to 10.14.2 in GitLab CI config
Edited by Dan Allen