gh_actions: export env variable to run ctest in parallel

.github/workflows/ccpp.yml

@@ -9,8 +9,9 @@ jobs:
     runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v1
-      - name: Build srsLTE on x86
+      - name: Build srsLTE on x86 Ubuntu 18.04
         run: |
+          export CTEST_PARALLEL_LEVEL=$(nproc --all)
           sudo apt update
           sudo apt install -y build-essential cmake libfftw3-dev libmbedtls-dev libpcsclite-dev libboost-program-options-dev libconfig++-dev libsctp-dev colordiff ninja-build valgrind
           mkdir build && cd build && cmake -DRF_FOUND=True -GNinja .. && ninja && ctest -T memcheck
@@ -22,8 +23,9 @@ jobs:
     runs-on: ubuntu-16.04
     steps:
       - uses: actions/checkout@v1
-      - name: Build srsLTE on x86
+      - name: Build srsLTE on x86 Ubuntu 16.04
         run: |
+          export CTEST_PARALLEL_LEVEL=$(nproc --all)
           sudo apt update
           sudo apt install -y build-essential cmake libfftw3-dev libmbedtls-dev libpcsclite-dev libboost-program-options-dev libconfig++-dev libsctp-dev colordiff ninja-build valgrind
           mkdir build && cd build && cmake -DRF_FOUND=True -GNinja .. && ninja && ctest -T memcheck
@@ -39,6 +41,7 @@ jobs:
         architecture: aarch64
         distribution: ubuntu18.04
         run: |
+          export CTEST_PARALLEL_LEVEL=$(nproc --all)
           apt update
           apt install -y build-essential cmake libfftw3-dev libmbedtls-dev libpcsclite-dev libboost-program-options-dev libconfig++-dev libsctp-dev ninja-build
           ls -l && pwd && mkdir build && cd build && cmake -DRF_FOUND=True -GNinja .. && ninja