[scripts/release] Allow umbrellas and files to generate info from a given sha. (#4961)
[scripts/release] Allow umbrellas and files to generate info from a given sha. (#4961)

The umbrellas command is fed in to the apidiff tool as a filter for which components to look at.

Prior to this change, the umbrellas command was ignoring the apidiff base sha and always generating results from origin/stable.

After this change, the umbrellas and files commands will both accept an optional base sha from which to generate results.

Tested by running:

```bash
./scripts/release umbrellas HEAD
# Should output nothing
```
material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios