Refactor package ruby-cri

Do not ship a license file with the package. Instead, install the license file
provided by the gem itself. Add `makedepends` and `options` arrays. Add a
comment explaining that one of namcap's warnings is spurious. Replace checksum
arrays `md5sums` and `sha1sums` with checksum array `sha256sums`. Reorder
variables, and remove some others entirely. Remove some quotation marks, convert
some double quotes to single quotes...