Linting should fail if pipeline module file is edited

[ewels]

In ewels/nf-core-methylseq#2 I have edited a module file that was pulled from nf-core/modules. I shouldn't be allowed to do this.

The linting warns me that something is amiss:

│ bismark/align                            │ modules/nf-cor… │ Local copy of   │
│                                          │                 │ module outdated │

But it should be checking the git sha in modules.json and recognising that it doesn't match what it expects. Then throwing a hard error.

Possible that the code for this is lurking in a PR that's waiting to be merged..

[ewels]

Done in #1373