Update Open Babel dependency & Continuous Integration

[KunhuanLiu]

To align with our interest to enhance MOFid in the future, it would be helpful to set up a workflow for updating Open Babel and conducting unit tests. Currently, MOFid utilizes Open Babel 2.4.0, whereas the latest version is 3.0.0, one version ahead.

Looks like Github has the option to automatically build and test through Actions / Continuous Integration. Setting up the relevant workflow could be helpful for future code functionality improvements.