Git workflow for editing pipeline more cleanly

[galengorski]

This is a generalized workflow for editing different parts of the pipeline more cleanly so that we can try to avoid multiple people working on the same part of the project. Also it's a place where I can put these git commands so I don't forget them.

• Working on 03b_model/src/run_model.py on a branch called model_edits and find that a change to 01_fetch/src/fetch_usgs_nwis.py is required
• on model_edits commit changes to run_model.py
• switch back to main branch on local
• create new branch (from the main branch) for small changes to fetch_usgs_nwis.py using git checkout -b fetch_changes
• make small changes to fetch, commit, push upstream fetch_changes creating new branch in remote repo
• merge small changes to fetch into remote repo main branch
• back on local, switch to main branch git checkout main
• pull the changes from remote repo in local main using git pull upstream main
• switch back to model_edits branch
• merge in new changes git merge main -m "merge small change to fetch nwis"

[amsnyder]

Works for me! Thanks for writing this up @galengorski