ci: add github test workflow

Signed-off-by: Paul Spooren <[email protected]>

.github/workflows/build.yml

@@ -0,0 +1,26 @@
+name: OpenWrt CI testing
+
+on: [ push, pull_request ]
+env:
+  CI_ENABLE_UNIT_TESTING: 0
+  CI_TARGET_BUILD_DEPENDS: libubox
+
+jobs:
+  native_testing:
+    name: Various native checks
+    runs-on: ubuntu-20.04
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: ynezz/[email protected]
+
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v2
+        if: failure()
+        with:
+          name: native-build-artifacts
+          if-no-files-found: ignore
+          path: |
+            build/scan
+            tests/cram/**/*.t.err