change from pip to built-in packages

Dockerfile

@@ -6,16 +6,12 @@ FROM php:apache
 RUN apt-get update && apt-get install -y \
         python3 \
         python3-pip \
+        python3-flask \
+        python3-yaml \
         nginx \
         supervisor \
     && rm -rf /var/lib/apt/lists/*
 
-# Install Python dependencies
-#     (add any other libraries you need here)
-RUN pip3 install --no-cache-dir \
-        flask \
-        pyyaml
-
 # Copy your application code & config files
 # Website Files
 COPY www/ /var/www/html