Minor fixes to the Dockerfile, Entrypoint and Readme

[gopuman]

Summary

This pull request introduces a few minor but important changes to enhance the overall functionality and user experience of the project.

Changes

1. Dockerfile Update:

   • Upgraded Bazel from version 5.0.0 to 6.0.0 to ensure compatibility with newer dependencies and provide access to the latest features and improvements.

2. Entrypoint Script:

   • Added a shebang (#!/bin/bash) to entrypoint.sh to clearly specify the script interpreter and prevent potential runtime errors on different systems.

3. Readme Documentation:

   • Introduced a new section in the README to address a potential error users might encounter, along with a recommended fix, improving troubleshooting support.

Rationale

These adjustments aim to keep the project up to date with current standards, enhance script execution reliability, and provide better guidance for users during setup.