GitHub default environment variables

Author: epompeii

.github/workflows/fork_pr_benchmarks_closed.yml

@@ -14,4 +14,4 @@ jobs:
           bencher archive \
           --project example \
           --token '${{ secrets.BENCHER_API_TOKEN }}' \
-          --branch '${{ github.head_ref }}'
+          --branch "$GITHUB_HEAD_REF"

.github/workflows/pr_benchmarks.yml

@@ -18,8 +18,8 @@ jobs:
           bencher run \
           --project example \
           --token '${{ secrets.BENCHER_API_TOKEN }}' \
-          --branch '${{ github.head_ref }}' \
-          --start-point '${{ github.base_ref }}' \
+          --branch "$GITHUB_HEAD_REF"
+          --start-point "$GITHUB_BASE_REF" \
           --start-point-hash '${{ github.event.pull_request.base.sha }}' \
           --start-point-clone-thresholds \
           --start-point-reset \

.github/workflows/pr_benchmarks_closed.yml

@@ -16,4 +16,4 @@ jobs:
           bencher archive \
           --project example \
           --token '${{ secrets.BENCHER_API_TOKEN }}' \
-          --branch '${{ github.head_ref }}'
+          --branch "$GITHUB_HEAD_REF"