v0.6.20

AlgebraOfGraphics v0.6.20

Diff since v0.6.19

Merged pull requests:

• add Dictionaries@0.4 to compat (#499) (@aplavin)
• Fix CI badge (#500) (@andreasnoack)
• Update permissions in CompatHelper.yml (#501) (@andreasnoack)
• bump version (#507) (@greimel)