No error output when failing to build

[pnorman]

Describe the bug When failing to build a style, charites exits with return code 1 but doesn't report any errors

To Reproduce Steps to reproduce the behavior:

1. Create an invalid style (see attached)
2. Build with charites build

Expected behavior Output to stderr indicating what failed

Charites Version:

• Charites version: 0.1.4

Desktop (please complete the following information):

• OS: Linux

name: Test
version: 8
sources:
  spirit:
    type: vector
    url: http://127.0.0.1:8000/tilejson.json
layers:
  - !!inc/file foo.yml
glyphs: https://go-spatial.github.io/carto-assets/fonts/{fontstack}/{range}.pbf

foo.yaml

  - id: building-fill
    source: spirit
  - id: building-outline
    source: spirit