Inform users about incompatibility between main and pip package

[sobolevnrm]

Our documentation suggests that most users install via the pip package. However, to run the examples, users need to clone the repo. Most will clone from main; however, this branch is generally out of sync with the pip package. For example, the pip-installed qdk-chemistry 1.0.2 does not work with examples/qpe_stretched_n2.ipynb from 7cd6603

We should consider one of the following approaches:

• Update the installation instructions to have users clone from stable (this puts an extra burden on the user)
• Provide the example content as a downloadable asset or package with each release