ci: bluetooth-tests: Run with GNU parallel

This commit updates the bluetooth-tests workflow to install the GNU
parallel utility to enable parallel execution of the Bluetooth tests.

Note that the Bluetooth test script automatically parallelises the
tests when `parallel` is available in the PATH; otherwise, it
sequentially executes the tests.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>

.github/workflows/bluetooth-tests.yaml

@@ -66,6 +66,12 @@ jobs:
           west update --path-cache /github/cache/zephyrproject 2>&1 1> west.update.log || west update --path-cache /github/cache/zephyrproject 2>&1 1> west.update.log || ( rm -rf ../modules ../bootloader ../tools && west update --path-cache /github/cache/zephyrproject)
           west forall -c 'git reset --hard HEAD'
 
+      - name: Install parallel
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y parallel
+          parallel --version
+
       - name: Run Bluetooth Tests with BSIM
         run: |
           export ZEPHYR_BASE=${PWD}