Fixup build paths and add to main readme

Author: PatrickLang

.github/workflows/build-raspi.yaml

@@ -0,0 +1,15 @@
+name: Build Rasperry Pi Sample
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Build for armv7-unknown-linux-gnueabihf
+      uses: actions-rs/cargo@v1
+      working-directory: ./examples-raspi
+      with:
+        use-cross: true
+        command: build
+        args: --target armv7-unknown-linux-gnueabihf

README.md

@@ -93,6 +93,10 @@ fn HardFault(ef: &ExceptionFrame) -> ! {
 
 ```
 
+## Raspberry Pi
+
+A sample project is available under [examples-raspi](./examples-raspi)
+
 ## License
 
 Licensed under either of