Update pyproject.toml dependencies

[stephengreen]

Adding the following dependencies, which are explicitly used in the code:

• requests
• asimov
• matplotlib

Removing:

• cryptography
• pyopenssl

@nihargupte-ph I think you added cryptography and pyopenssl in #121, where you put a fixed version. Is this still needed?

[stephengreen]

asimov also depends on htcondor, which on pypi only exists for Linux. Maybe we should not have asimov as a dependency then. In that case, we should handle the imports appropriately.

@max-dax @jonaswildberger What do you think?

[mpuerrer]

I think we should avoid requiring dependencies such as htcondor because it is not needed for all use cases of dingo and will make it hard for people to try out the code. Such dependencies should be optional and could be listed in the README and docs.

[stephengreen]

Good point, I removed Asimov from the dependencies.