Expand linting workflow to check for PSR-4/PSR-0 autoloading compliance

In the linting workflow we should add a check to see if all our classes are conforming to the PRS-4/PSR-0 autoloading rules.

This can be done with a simple step in our workflow
```
      - name: Validate conforming class autoloading
        run: composer dump-autoload --optimize --strict-psr --strict-ambiguous
```