fix(rathole): install python3 for built-in health endpoint

CloudronPackages/Rathole/Dockerfile

@@ -5,7 +5,7 @@ ARG ARCH=x86_64-unknown-linux-gnu
 
 USER root
 RUN apt-get update \
- && apt-get install -y --no-install-recommends curl ca-certificates tar \
+ && apt-get install -y --no-install-recommends curl ca-certificates tar python3 \
  && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app/pkg
@@ -40,4 +40,3 @@ HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 \
   CMD curl -fsS http://127.0.0.1:${APP_PORT}/ || exit 1
 
 CMD ["/app/pkg/start.sh"]
-