fix: propagate docker exit code from bats pipeline with pipefail

Pipeline 'tar | docker | tee' previously always returned tee's exit
code (0), masking test failures in the bats job. set -o pipefail
makes 0 capture the last failed command's exit code instead.

.gitea/workflows/quality-gate.yml

@@ -50,6 +50,7 @@ jobs:
         shell: bash
         run: |
           set +e
+          set -o pipefail
           mkdir -p "reports/${GITHUB_SHA:0:8}/bats"
           tar cf - . | docker run --rm -i \
             --entrypoint bash ${{ inputs.bats-image }} \
@@ -60,7 +61,7 @@ jobs:
             apk add -q lsof python3 jq curl ruby
             bats tests/
           ' 2>&1 | tee "reports/${GITHUB_SHA:0:8}/bats/results.txt"
-          BATS_EXIT=${PIPESTATUS[1]}
+          BATS_EXIT=$?
           bash .ci/.gitea/scripts/bats-report.sh "reports/${GITHUB_SHA:0:8}/bats" || true
 
           STATE="success"