Do not require schema path (fix #1838)

[apeltzer]

PR checklist

• [ ] This comment contains a description of changes (with reason)
• [ ] CHANGELOG.md is updated
• [ ] If you've fixed a bug or added code that should be tested, add tests!
• [ ] Documentation in docs is updated

[codecov[bot]]

Codecov Report

Merging #1839 (e488379) into dev (75143a4) will decrease coverage by 4.49%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              dev    #1839      +/-   ##
==========================================
- Coverage   69.25%   64.75%   -4.50%     
==========================================
  Files          59       34      -25     
  Lines        7148     4100    -3048     
==========================================
- Hits         4950     2655    -2295     
+ Misses       2198     1445     -753     

Impacted Files	Coverage Δ
nf_core/__main__.py	53.50% <100.00%> (ø)
nf_core/lint/nextflow_config.py
nf_core/lint/files_unchanged.py
nf_core/modules/__init__.py
nf_core/modules/remove.py
nf_core/lint/actions_ci.py
nf_core/modules/patch.py
nf_core/__init__.py
nf_core/lint/actions_schema_validation.py
nf_core/modules/list.py
... and 16 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.