Update bitbucket-pipelines.yml

It is definitions :)

Author: erwinromkes

templates/bitbucket-pipelines.yml

@@ -1,7 +1,7 @@
 # See https://quay.io/repository/hypernode/deploy?tab=tags for all possible tags.
 image: quay.io/hypernode/deploy:3-php8.2-node18
 
-definition:
+definitions:
   steps:
     - step: &hypernode-build
         name: Build