Add CI builds for default and via keymaps (#20071)

.github/workflows/ci_builds.yml

@@ -0,0 +1,38 @@
+name: CI Builds
+
+permissions:
+  contents: read
+
+on:
+  push:
+    branches:
+    - master
+    - develop
+
+jobs:
+  ci_builds:
+    runs-on: self-hosted
+
+    if: github.repository == 'qmk/qmk_firmware'
+
+    strategy:
+      matrix:
+        keymap:
+        - default
+        - via
+
+    container: qmkfm/qmk_cli
+
+    steps:
+    - name: Disable safe.directory check
+      run : git config --global --add safe.directory '*'
+
+    - uses: actions/checkout@v3
+      with:
+        submodules: recursive
+
+    - name: Install dependencies
+      run: pip3 install -r requirements.txt
+
+    - name: Run `qmk mass-compile` (keymap ${{ matrix.keymap }})
+      run: qmk mass-compile -j $(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || getconf _NPROCESSORS_ONLN 2>/dev/null) -km ${{ matrix.keymap }}