Renaming sample metadata file in the moving pictures tutorial?

[fedarko]

Improvement Description
Making a small fix to the sample metadata's filename in the moving pictures tutorial.

Current Behavior
Currently, the sample metadata is stored at the link https://data.qiime2.org/2020.2/tutorials/moving-pictures/sample_metadata.tsv, but the tutorial asks users to save this file as sample-metadata.tsv (with a - rather than a _). This has caused confusion to users (including me at one point a few months back).

Proposed Behavior
Storing the sample metadata at https://data.qiime2.org/2020.2/tutorials/moving-pictures/sample-metadata.tsv (so that just e.g. running wget on the link without the -O option will still download a correctly-named file).

Comments
I'm aware that at this point the "default" sample_metadata.tsv location might already be baked in to other tutorials that use the moving pictures data, and that changing this at this point might be too much work for its own good -- please feel free to close this if so :)

References

1. https://forum.qiime2.org/t/issue-with-loading-the-file-sample-metadata-tsv-as-metadata-from-moving-pictures-tutorial/14226