bump codecov to ~> 0.2, since 0.1.X are all yanked

[peterberkenbosch]

according to https://rubygems.org/gems/codecov/versions all the 0.1.X gems are yanked.

This PR updated the dependency to 0.2

[mergify]

It looks like this PR is missing a label to determine the type of change it introduces. The maintainer should add one of the following labels:

• bug for bugfixes.
• enhancement for new features and improvements.
• documentation for documentation changes.
• security for security patches.
• removed for feature removals.
• infrastructure for internal changes that should not go in the changelog.

Additionally, the maintainer may also want to add one of the following:

• breaking for breaking changes.
• deprecated for feature deprecations.

Once the correct labels have been set, simply remove the needs changelog label label from this PR so I can merge it.

[elia]

The failure on master is unrelated, I'll force-merge this as it's preventing all extension PRs from passing. Wondering how they ended up with such a dramatic decision 🙀

[brchristian]

Wow, this is one of the stranger things I've ever seen.

@elia Any chance we could get a new rubygems release with this PR in it? It looks like most extensions with dependencies on solidus_dev_support are still failing CI because they're looking for a compatible gem version.