Allow crystal ">= 0.31.1" in shard.yml

[HashNuke]

• Updated the shard.yml to allow Crystal v1.
• But the new version specification also retains the compatibility with the currently mentioned 0.31.1 version.

[HashNuke]

• I just noticed there's an issue (Crystal 1.0 support? #3) about crystal 1.0 support and also another open PR (bump crystal requirement for 1.0 compatibility #4) that has the same change as this PR.
• Being able to add 1.0 support for icr, depends on this library adding support for 1.0.

I would love to contribute if there is anything else we can do to help move forward on this PR or #4.

[taylor]

@ryanprior @ftarulla is there anything needed before this is merged?