Heads up: Example links on matminer page broken

I was looking at the matminer page and noticed that most (I only check a few) links pointing to examples are broken (e.g. matminer (Materials Data Mining) — matminer 0.6.5 documentation). For example, the example index (https://nbviewer.jupyter.org/github/hackingmaterials/matminer_examples/blob/master/matminer_examples/index.ipynb) gives a 404 Error. I suspect that a common header is broken and hopefully it will be easy to fix.

Just replace master to main.

I’ve sent a PR recently: (1.) Fix links to example ipynbs from *master* to *main* branch in Nbviewer, (2.) Fix MPDS retrieval by blokhin · Pull Request #621 · hackingmaterials/matminer · GitHub