Change Paralell constraints generation to sequential (apache#46223)

Parallel constraint generation runs several docker containers
and it produces some build artifacts in paralllel (when compiling spar)
that are huge - when run in parallell we are runnig out of disk
space for them. Changing to sequential execution hopefully shoudl
fix it.

.github/workflows/generate-constraints.yml

@@ -112,9 +112,11 @@ jobs:
         env:
           CHICKEN_EGG_PROVIDERS: ${{ inputs.chicken-egg-providers }}
         run: >
-          breeze release-management generate-constraints --run-in-parallel
-          --airflow-constraints-mode constraints --answer yes
-          --chicken-egg-providers "${CHICKEN_EGG_PROVIDERS}" --parallelism 3
+          for PYTHON in $PYTHON_VERSIONS; do
+            breeze release-management generate-constraints
+            --airflow-constraints-mode constraints --answer yes
+            --chicken-egg-providers "${CHICKEN_EGG_PROVIDERS}"
+          done
       - name: "Dependency upgrade summary"
         shell: bash
         env:
@@ -123,6 +125,7 @@ jobs:
           for PYTHON_VERSION in $PYTHON_VERSIONS; do
             echo "Summarizing Python $PYTHON_VERSION"
             cat "files/constraints-${PYTHON_VERSION}"/*.md >> $GITHUB_STEP_SUMMARY || true
+            df -H
           done
       - name: "Upload constraint artifacts"
         uses: actions/upload-artifact@v4