codal_app: Update codal-microbit-v2 to v0.2.42.

Changes to codal-microbit-v2 and codal-core include:

- Fixed an off-by-one error in FiberLock whereby a semaphore-mode
  lock would have 1 slot fewer than expected
- Fixed an off-by-one error in the device pacic codes in MicroBitError,
  where all hw specific codes were one higher than needed (leaving code 50 empty)
- Added a new deepSleep() call to support a kind of interruptable deep sleep mode
- Minor build.py patch to show --status without pagenation
- Improved sound level detection sensitivity to 35db from 52db,
  re-calibrated parameters for accuracy,
  and introduced optional 8 bit range sound level API
- Merged a new NRF52LEDMatrix::rotateTo function (Thanks Martin!)

https://github.com/lancaster-university/codal-microbit-v2/releases/tag/v0.2.42

Author: microbit-carlos

src/codal_app/codal.json

@@ -2,7 +2,7 @@
     "target": {
         "name": "codal-microbit-v2",
         "url": "https://github.com/lancaster-university/codal-microbit-v2",
-        "branch": "v0.2.40",
+        "branch": "v0.2.42",
         "type": "git",
         "test_ignore": true
     } ,