1a1c4614

Fix `PROJECT_ROOT` (#158)

There were a few bugs around setting `PROJECT_ROOT`, such that it was
effectively always the directory `project-manager` was run from, which
isn’t ideal.

By looking up the root and setting the var directly in the `if`
condition (as recommended by
[Shellcheck](https://www.shellcheck.net/wiki/SC2181)), we avoid the
fragility of suspending `trap` and disabling `-e`.

And now passing `--verbose` causes `PROJECT_ROOT` to be displayed.