Include cstddef in PacketParser.cpp to fix error about size_t

.github/workflows/build.yaml

@@ -0,0 +1,18 @@
+name: RFPowerView CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.12'
+      - name: Install PlatformIO
+        run: pip install --upgrade platformio
+
+      - name: Run RFPowerView tests
+        run: pio test --environment native

src/PacketParser.cpp

@@ -1,4 +1,5 @@
 #include "PacketParser.h"
+#include <cstddef>
 
 PacketParser::PacketParser()
 {