[MINOR] Add license for dagre-d3 and graphlib-dot
[MINOR] Add license for dagre-d3 and graphlib-dot

Add license for dagre-d3 and graphlib-dot

Author: zsxwing <zsxwing@gmail.com>

Closes #6539 from zsxwing/LICENSE and squashes the following commits:

82b0475 [zsxwing] Add license for dagre-d3 and graphlib-dot

(cherry picked from commit d1d2def2f5f91e86f340656421170d1097f14854)
Signed-off-by: Andrew Or <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@databricks.com>

andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap