Add the scorecard and dependabot workflows

[gcanlin]

Related to #197, I add the scorecard and dependabot workflows. Scorecard helps automatically assess and improve project security and quality with every code change.

[gcanlin]

If you set up this configuration, it will send a report to help you improve the security of your project as the following picture shows. Besides, it can also help promote your project by reducing users’ security concerns.