Pin add-variable-declarations to v1.5.0.
Pin add-variable-declarations to v1.5.0.

Fixes #223.

decaffeinate/decaffeinate,eventualbuddha/decaffeinate,eventualbuddha/decaffeinate,alangpierce/decaffeinate,alangpierce/decaffeinate,decaffeinate/decaffeinate,alangpierce/decaffeinate