ci: heredoc syntax "<<<" also seems to be a bash-ism

Author: rjaegers

.github/workflows/wc-build-push.yml

@@ -105,7 +105,7 @@ jobs:
         id: devcontainer-metadata
       - run: echo "git-commit-epoch=$(git log -1 --pretty=%ct)" >> "$GITHUB_OUTPUT"
         id: devcontainer-epoch
-      - run: echo "arch=$(tr '[:upper:]' '[:lower:]' <<< "${RUNNER_ARCH}")" >> "$GITHUB_OUTPUT"
+      - run: echo "arch=$(echo "${RUNNER_ARCH}" | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_OUTPUT"
         id: devcontainer-arch
       - uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         id: build-and-push

.github/workflows/wc-integration-test.yml

@@ -52,7 +52,7 @@ jobs:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
           persist-credentials: false
-      - run: echo "arch=$(tr '[:upper:]' '[:lower:]' <<< "${RUNNER_ARCH}")" >> "$GITHUB_OUTPUT"
+      - run: echo "arch=$(echo "${RUNNER_ARCH}" | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_OUTPUT"
         id: runner-arch
       - run: bats --formatter junit "${TEST_FILE}" | tee "test-report-${IMAGE_BASENAME}-${RUNNER_ARCH}.xml"
         env: