.github/test-pr: increase test parallelism

Author: ehildenb

.github/workflows/test-pr.yml

@@ -142,7 +142,7 @@ jobs:
       - name: 'Build distribution'
         run: docker exec -u github-user kevm-ci-haskell-${{ matrix.test-suite }}-${{ github.sha }} /bin/bash -c 'CXX=clang++-14 poetry -C kevm-pyk run kdist --verbose build -j`nproc` evm-semantics.plugin evm-semantics.haskell'
       - name: 'Prove Haskell'
-        run: docker exec -u github-user kevm-ci-haskell-${{ matrix.test-suite }}-${{ github.sha }} /bin/bash -c "make ${{ matrix.test-suite }} PYTEST_ARGS='-vv ${{ matrix.test-args }}' PYTEST_PARALLEL=4"
+        run: docker exec -u github-user kevm-ci-haskell-${{ matrix.test-suite }}-${{ github.sha }} /bin/bash -c "make ${{ matrix.test-suite }} PYTEST_ARGS='-vv ${{ matrix.test-args }}' PYTEST_PARALLEL=6"
       - name: 'Tear down Docker'
         if: always()
         run: |