add action builds

with docker img containing dynamic uClibc toolchain

.github/workflows/c-cpp.yml

@@ -0,0 +1,20 @@
+
+name: CI Build
+
+on: [push, pull_request]
+
+jobs:   
+  build-modern:
+    name: FBA for MiyooCFW (uClibc)
+    runs-on: ubuntu-20.04
+    container:
+      image: nfriedly/miyoo-toolchain:steward
+    steps:
+    - uses: actions/checkout@v3
+    - name: build
+      run: make -f Makefile
+    - uses: actions/upload-artifact@v3
+      with:
+        name: FBA binary
+        path: bin/fba
+        if-no-files-found: error # 'error', 'warn', 'ignore'; defaults to `warn`