Update Dockerfile to use python=3.8

Based on https://github.com/fmegahed/tavr_paper/blob/main/package-list.txt; this seems to be the range of python versions used to support the pycaret==2.3.6

Dockerfile

@@ -1,18 +1,12 @@
-# Use latest Python 3.11 patch release from the official image line
-FROM python:3.11-slim
+FROM python:3.8-slim
 
-# Avoid interactive prompts during apt installs
 ENV DEBIAN_FRONTEND=noninteractive
-
-# Gradio defaults (HF Spaces expects port 7860)
 ENV GRADIO_SERVER_NAME=0.0.0.0
 ENV GRADIO_SERVER_PORT=7860
 ENV PYTHONUNBUFFERED=1
 ENV PIP_NO_CACHE_DIR=1
 
-WORKDIR /app
-
-# System deps that commonly help with pycaret[full] and its optional deps
+# Needed to install older scikit-learn builds (may compile) and common ML deps
 RUN apt-get update && apt-get install -y --no-install-recommends \
     build-essential \
     gcc g++ \
@@ -26,23 +20,27 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     libxrender1 \
   && rm -rf /var/lib/apt/lists/*
 
-# Copy dependency files first for better Docker layer caching
+WORKDIR /app
+
 COPY requirements.txt /app/requirements.txt
 
-# Upgrade pip tooling
 RUN python -m pip install --upgrade pip setuptools wheel
 
-# Install pycaret full + gradio explicitly.
-# Your requirements.txt currently lists "scikit-learn" and "pycaret" :contentReference[oaicite:2]{index=2},
-# but you asked specifically for pycaret[full].
+# Workaround for pycaret 2.3.6 pulling deprecated 'sklearn' package in some cases
+# See the error guidance referenced in PyCaret issue threads. :contentReference[oaicite:3]{index=3}
+ENV SKLEARN_ALLOW_DEPRECATED_SKLEARN_PACKAGE_INSTALL=True
+
+# Pin versions to match the older model ecosystem
+# - pycaret==2.3.6 per your note
+# - gradio pinned to a 3.x line (3.x works on Python>=3.7). :contentReference[oaicite:4]{index=4}
+# - scikit-learn pinned to 0.23.2 which PyCaret 2.x historically targeted. :contentReference[oaicite:5]{index=5}
 RUN python -m pip install \
-    "pycaret[full]" \
-    gradio \
+    "pycaret==2.3.6" \
+    "scikit-learn==0.23.2" \
+    "gradio==3.50.2" \
     -r /app/requirements.txt
 
-# Copy the rest of the repo (app.py, csv, pkl, etc.)
 COPY . /app
 
 EXPOSE 7860
-
 CMD ["python", "app.py"]