Using `buffrs add` with --registry option on old format Proto.toml raises an error

[alexespencer]

To recreate: Remove the registry = line from Proto.toml.

Run something like: buffrs add --registry https://helsing.jfrog.io/artifactory inf-proto-playground/units@=0.0.1

Error:

Error:
   0: Failed to parse manifest
   1: TOML parse error at line 1, column 1
   1:   |
   1: 1 | [dependencies.units]
   1:   | ^^^^^^^^^^^^^^^^^^^^
   1: missing field `registry`
   1:

Work around fix: Remove the package manually from Proto.toml then try again with buffrs add

[alexespencer]

Or, delete Proto.toml and do buffrs init then buffrs add.

In fact, running buffrs add BEFORE buffrs init doesn't return a nice error - I'll raise another issue