devel/rubygem-sprockets-rails: Update from 3.0.4 to 3.1.1

3.1.1

• Only set the gzip option if the sprockets version supports it.

3.1.0

• Improve error message when manifest file is not present.
• Improve error message when asset is not linked.
• Allow gzip compression to be disabled from Rails configuration.
• Add option to make raising exception for missing assets optional.
• Merge quite_assets gem feature.
• Allow SRI integrity attribute on localhost.

Approved by: swills (mentor)