pegasus/ci: make Jenkins shell steps POSIX-compatible

Jenkinsfile

@@ -63,7 +63,7 @@ spec:
       steps {
         container('go-tester') {
           sh '''
-            set -euo pipefail
+            set -eu
             mkdir -p build
             cd backend
             go install github.com/jstemmer/go-junit-report/v2@latest
@@ -88,7 +88,7 @@ spec:
       steps {
         container('node-tester') {
           sh '''
-            set -euo pipefail
+            set -eu
             mkdir -p build
             cd frontend
             npm ci
@@ -112,7 +112,7 @@ spec:
       steps {
         container('publisher') {
           sh '''
-            set -euo pipefail
+            set -eu
             python - <<'PY'
 import json
 from pathlib import Path
@@ -154,7 +154,7 @@ PY
       steps {
         container('publisher') {
           sh '''
-            set -euo pipefail
+            set -eu
             python scripts/publish_test_metrics.py
           '''
         }
@@ -165,7 +165,7 @@ PY
       steps {
         container('publisher') {
           sh '''
-            set -euo pipefail
+            set -eu
             backend_rc="$(cat build/backend-test.rc 2>/dev/null || echo 1)"
             frontend_rc="$(cat build/frontend-test.rc 2>/dev/null || echo 1)"
             if [ "${backend_rc}" -ne 0 ] || [ "${frontend_rc}" -ne 0 ]; then