Support for Crystal 1.0

[jwoertink]

The version specified in the shard.yml will fallback to crystal (~> 0.35, >= 0.35.1) by default.

https://github.com/hugoabonizio/schedule.cr/blob/64d69b6e7548566259a562d700736d76c165446c/shard.yml#L7

For this to work with Crystal 1.0, it'll need to be changed to crystal: ">= 0.35.1"

[phil294]

while this makes sense, crystal never complained to me when I used this library in a 1.x project.

[jwoertink]

We couldn't get specs to pass with it on Cable.cr without changing this. We ended up just removing this shard as a dependency.