cargo-config: rename to config.toml

[stefano-garzarella]

Summary of the PR

cargo recently complains about our cargo configuration file name:

$ cargo build
warning: `vhost/.cargo/config` is deprecated in favor of
`config.toml`
note: if you need to support cargo 1.38 or earlier, you can
symlink `config` to `config.toml`

As suggested, let's update the file name.

Requirements

Before submitting your PR, please make sure you addressed the following
requirements:

• All commits in this PR have Signed-Off-By trailers (with
  git commit -s), and the commit message has max 60 characters for the
  summary and max 75 characters for each description line.
• All added/changed functionality has a corresponding unit/integration
  test.
• All added/changed public-facing functionality has entries in the "Upcoming
  Release" section of CHANGELOG.md (if no such section exists, please create one).
• Any newly added unsafe code is properly documented.

[stefano-garzarella]

Gentle ping :-) it's an easy one

[roypat]

I don't think the symlink is needed :D

$ cargo +1.38.0 build 
error: failed to parse manifest at `/home/ANT.AMAZON.COM/roypat/Development/rust-vmm/vhost/vhost/Cargo.toml`

Caused by:
  failed to parse the `edition` key

Caused by:
  supported edition values are `2015` or `2018`, but `2021` is unknown

[stefano-garzarella]

I don't think the symlink is needed :D

Good point :-D

I'll remove the symlink!

$ cargo +1.38.0 build 
error: failed to parse manifest at `/home/ANT.AMAZON.COM/roypat/Development/rust-vmm/vhost/vhost/Cargo.toml`

Caused by:
  failed to parse the `edition` key

Caused by:
  supported edition values are `2015` or `2018`, but `2021` is unknown

[stefano-garzarella]

v2:

• removed the symlink [@roypat]

[roypat]

nit: commit title still says "and add a symlink" (approving because you can update commit messages without dismissing approvals on github :)

[stefano-garzarella]

nit: commit title still says "and add a symlink" (approving because you can update commit messages without dismissing approvals on github :)

uff, it's monday, no wait it's not ;-P

fixed, thanks! :-)