Check some easily misconfigured file contents

[edthedev]

Closes #110

[edthedev]

Per discussion, we might check for common app.json errors in this manner, as well:

{"failed": true, "message": "'app.json' failed validation on value 'main_module'"}
make: *** [Makefile:85: deploy] Error 1

from https://github.com/techservicesillinois/secops-splunk-domainblock/actions/runs/20145824030/job/57825807888?pr=20

"python_version": "3.13"

from
techservicesillinois/phantom-toolbox#37