Implement carmel pin Module@version

[miyagawa]

Imagine you have cpanfile:

requires 'JSON', '4';

and the snapshot has the version 4.00.

You can update to the latest version available from CPAN with carmel update JSON. Let's say you don't want the version on CPAN today, and want to pin to a specific version. You can update cpanfile:

requires 'JSON', '== 4.04';

This works fine, but then you need to unpin every time you update to newer versions.

The new carmel pin command allows you to keep the version specification in cpanfile (so that future run of carmel update will update to the latest), while pinning to the specified version, rather than whatever is the latest on CPAN when you run it.

carmel pin JSON@4.04 is essentially the same as:

• manually update cpanfile to have requires 'JSON', '== 4.04';
• run carmel install to pin the JSON version in the snapshot
• revert cpanfile to requires 'JSON', '4';