Adds <blockquote> and <cite> to Lucky::BaseTags

[rmarronnier]

Fixes #1316
Adds <blockquote> and <cite> html tags to Lucky::BaseTags.

Checklist

• - An issue already exists detailing the issue/or feature request that this PR fixes
• - All specs are formatted with crystal tool format spec src
• - Inline documentation has been added and/or updated
• - Lucky builds on docker with ./script/setup
• - All builds and specs pass on docker with ./script/test

[stephendolan]

This looks good to me. Thank you for keeping the list in alphabetical order 👍

We'll wait for one more approval and then get it merged!