To allow regenerating good fixtures, move the bad fixtures to
their own directory.

As per [`proto3`'s language guide](https://developers.google.com/protocol-buffers/docs/proto3#specifying_field_rules):

> Message fields can be one of the following:
>  - singular: a well-formed message can have zero or one of this field (but not more than one). And this is the default field rule for proto3 syntax.

This means that all `proto3` fields are effectively optional when
writing, so it's relatively easy to implement by accepting a `Partial`
version of the message interface for encoding.

When reading messages singular fields are initialized to their default
values when reading and optional values are not so the plain non-`Partial`
interface can be returned.

This also has the nice side effect of not requiring the user to pass
empty lists/maps for `repeated` and `map` fields which never really
felt right.  These values are initialized to their empty forms when
reading messages from the wire.

Fixes #42

ipfs/eslint-config-ipfs#126 will introduce
linting rules on import sorting so order imports during building
in a way that will comply with the new linting rules.

## [protons-runtime-v5.0.0](protons-runtime-v4.0.2...protons-runtime-v5.0.0) (2023-02-02)

### ⚠ BREAKING CHANGES

* singular fields should be optional to write (#83)

### Bug Fixes

* singular fields should be optional to write ([#83](#83)) ([229afbc](229afbc)), closes [#42](#42)
* sort imports ([#84](#84)) ([6f796f1](6f796f1))

## [protons-v7.0.0](protons-v6.1.3...protons-v7.0.0) (2023-02-02)

### ⚠ BREAKING CHANGES

* singular fields should be optional to write (#83)

### Bug Fixes

* singular fields should be optional to write ([#83](#83)) ([229afbc](229afbc)), closes [#42](#42)
* sort imports ([#84](#84)) ([6f796f1](6f796f1))
* update sibling dep versions ([a77d027](a77d027))

### Trivial Changes

* move bad fixtures to separate directory ([#82](#82)) ([76aa198](76aa198))