Fix calculation of daily new infections

[cjbayesian]

Current daily new infections are being calculated as $I_{t+1} - I_{t}$, which doesn't account for the infected cases transitioning into recovered during that time step. The calculations should be $I_{new} = (I_{t+1} - I_{t}) + (R_{t+1} - R_{t})$

[cjbayesian]

chime/src/penn_chime/models.py

Line 88 in 7f7e33e

projection_admits = projection.iloc[:-1, :] - projection.shift(1)

[cjbayesian]

Not apples to apples, but here is the fixed output on the pre-refactored code:

[cjbayesian]

Working on getting the fix implemented on refactored code.

[PhilMiller]

Please add the 'models' label to this, so I can link to models Correct/improve the underlying models in the app header, and have it reflect the list of changes