Add github workflow

Author: PetteriAimonen

.github/workflows/build.yml

@@ -0,0 +1,44 @@
+name: Build Pico2 logic sniffer firmware
+
+on:
+    push:
+    workflow_dispatch:
+    pull_request:
+
+jobs:
+    build_firmware:
+        name: Build Pico2 logic sniffer firmware
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Check out code from GitHub
+              uses: actions/checkout@v4
+            
+            - name: Install platformio
+              run: |
+                pip install -U platformio
+            
+            - name: Build firmware
+              run: |
+                pio run
+                cp .pio/build/pico2/firmware.elf pico2_logic_sniffer.elf
+                cp .pio/build/pico2/firmware.uf2 pico2_logic_sniffer.uf2
+        
+            - name: Test decoder script
+              run: |
+                python utils/decode_sniff.py utils/testdata/sniff_700Hz_567kHz.dat
+
+            - name: Upload binaries into build artifacts
+              uses: actions/upload-artifact@v4
+              with:
+                path: pico2_logic_sniffer.*
+                name: Pico2 logic sniffer firmware
+        
+            - name: Upload to newly created release
+              env:
+                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+              if: ${{ startsWith(github.ref, 'refs/tags/') }}
+              run: |
+                RELEASE=$(basename ${{github.ref}})
+                gh release upload --repo ${GITHUB_REPOSITORY} $RELEASE pico2_logic_sniffer.*
+