Update README for YOLO FastAPI demo

Dockerfile

@@ -1,13 +1,13 @@
-# Use the official Python image
+# Add a unique comment to force a rebuild
+# CACHE BUSTER: 2025-09-17-01
 FROM python:3.12-slim
 
-# Install system dependencies needed for libraries like opencv-python and potential builds
+# Install system dependencies needed for libraries like opencv-python
 RUN apt-get update && apt-get install -y \
     libglib2.0-0 \
     libsm6 \
     libxext6 \
     libxrender1 \
-    build-essential \
     && rm -rf /var/lib/apt/lists/*
 
 # Set the working directory
@@ -15,7 +15,7 @@ WORKDIR /app
 
 # Copy requirements.txt and install dependencies
 COPY requirements.txt .
-RUN pip install --no-cache-dir -r requirements.txt
+RUN pip install --no-cache-dir --upgrade -r requirements.txt
 
 # Copy the rest of the application code
 COPY . .