Use the right branch for fetching dependencies

.buildkite/pipeline.yaml

@@ -37,6 +37,7 @@ steps:
     plugins:
       - docker#v3.0.1:
           image: "node:10"
+          propagate-environment: true
 
   - label: "🔧 Riot Tests"
     command:
@@ -56,3 +57,4 @@ steps:
     plugins:
       - docker#v3.0.1:
           image: "node:10"
+          propagate-environment: true

scripts/fetchdep.sh

@@ -17,10 +17,8 @@ clone() {
     fi
 }
 
-# Try the PR author's branch in case it exists on the deps as well.
-clone $TRAVIS_PULL_REQUEST_BRANCH
 # Try the target branch of the push or PR.
-clone $TRAVIS_BRANCH
+clone $BUILDKITE_BRANCH
 # Try the current branch from Jenkins.
 clone `"echo $GIT_BRANCH" | sed -e 's/^origin\///'`
 # Use the default branch as the last resort.