Add pico CI action

.github/actions/pico/action.yml

@@ -0,0 +1,16 @@
+name: Install and build Zephyr dependencies
+description: Install and build Zephyr dependencies
+runs:
+  using: "composite"
+  steps:
+    - name: Install packages
+      run: |
+        sudo apt-get update && sudo apt-get upgrade
+        sudo apt-get install -y --no-install-recommends git cmake tar buil-essentials \
+          gcc-arm-none-eabi libnewlib-arm-none-eabi libstdc++-arm-none-eabi-newlib
+      shell: bash
+    - name: Install pico-sdk
+      run: | 
+        git clone https://github.com/raspberrypi/pico-sdk /opt/pico-sdk
+        echo "PICO_SDK_PATH=/opt/pico-sdk" >> $GITHUB_ENV 
+      shell: bash

.github/workflows/pico.yml

@@ -0,0 +1,22 @@
+name: Pico examples
+
+on:
+  pull_request:
+
+jobs:
+  ci:
+    name: Build Pico examples
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          submodules: recursive
+      - name: Install dependencies
+        uses: ./.github/actions/zephyr
+      - name: Build examples
+        run: |
+          cd examples/pico
+          cmake -Bbuild && cd build
+          make
+