Fix wrong variable name in set-automatic-deploys GitHub workflow.
Fix wrong variable name in set-automatic-deploys GitHub workflow.

This fixes a bug where the `Set automatic deploys` workflow would always
disable automatic deploys even with the input `setAutomaticDeploys=enable`.

Tested: ran from branch, observed that the webhook is now called with
`AUTOMATIC_DEPLOYS_ENABLED: true` when `setAutomaticDeploys=enable`
(https://github.com/alphagov/collections/actions/runs/3471035053/jobs/5799996274)

alphagov/local-links-manager,alphagov/local-links-manager,alphagov/local-links-manager