[Bug]: Local development setup fails on a fresh clone due to missing setuptools pin

Description

On a fresh clone, pip install -r requirements.txt succeeds but
python -m mkdocs build fails with:

ModuleNotFoundError: No module named 'pkg_resources'

markdown==3.2.1 requires pkg_resources, which setuptools removed in
version 82.0.0. setuptools is not pinned in en/requirements.txt, so pip
installs the latest version.

The Dockerfile already pins setuptools<80, so container builds are fine —
only local setup is broken. Existing contributors don't see this because their
virtual environments already have an older setuptools.

Fix: add setuptools<80 to en/requirements.txt to match the Dockerfile.

Steps to Reproduce

1. Clone the repository:

   git clone https://github.com/wso2/docs-api-platform.git

2. Create and activate a virtual environment:

   cd docs-api-platform
   python3 -m venv venv
   source venv/bin/activate

3. Install the dependencies:

   cd en
   pip install -r requirements.txt

4. Build the site:

   python -m mkdocs build

Result: the build fails with:

   File ".../site-packages/markdown/core.py", line 26, in <module>
       import pkg_resources
   ModuleNotFoundError: No module named 'pkg_resources'

Version

main @ 5aab8ab

Environment Details (with versions)

OS: Ubuntu 24.04
Python 3.12.11, pip 26.2.1, setuptools 84.0.0, markdown 3.2.1, mkdocs 1.4.2

Start with en/requirements.txt and compare its dependency pins with the existing setuptools<80 pin in the Dockerfile. Recreate the fresh virtual-environment setup, run pip install -r requirements.txt, and verify python -m mkdocs build completes without the pkg_resources error.