build.yml: Try checkout in workflow

Try to checkout to the PR so that this workflow runs on that branch as
well and not only the repo's default branch.

Signed-off-by: Dhruva Gole <goledhruva@gmail.com>

Author: DhruvaG2000

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Build
+name: Build Test
 
 on: [push, pull_request]
 
@@ -9,11 +9,6 @@ jobs:
     env:
       CMAKE_PREFIX_PATH: /opt/toolchains
     steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-        with:
-          path: Arduino-Zephyr-API
-
       - name: Initialize
         working-directory: Arduino-Zephyr-API
         run: |
@@ -24,6 +19,14 @@ jobs:
           mv ArduinoCore-API/api/tmpArduinoAPI.h ArduinoCore-API/api/ArduinoAPI.h
           cp -r ArduinoCore-API/api modules/lib/Arduino-Zephyr-API/cores/arduino/.
 
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 0
+          persist-credentials: false
+          path: modules/lib/Arduino-Zephyr-API
+
       - name: Build fade
         working-directory: Arduino-Zephyr-API
         run: |