This allows users to specify platform in a more humane way, for example:
```yaml
env:
  # equals to `linux/amd64, linux/arm/v6`
  platforms: >
    linux/amd64,
    linux/arm/v6

- uses: docker/setup-qemu-action@v2
  with:
    platforms: ${{ env.PLATFORMS }}
```

Signed-off-by: Chocobo1 <[email protected]>

Trim off spaces in  `platforms` string

Signed-off-by: CrazyMax <[email protected]>

readme: fix badge

Signed-off-by: CrazyMax <[email protected]>

Signed-off-by: CrazyMax <[email protected]>

Signed-off-by: CrazyMax <[email protected]>

Signed-off-by: CrazyMax <[email protected]>

switch to actions-toolkit implementation

Bumps [@docker/actions-toolkit](https://github.com/docker/actions-toolkit) from 0.1.0-beta.14 to 0.1.0.
- [Release notes](https://github.com/docker/actions-toolkit/releases)
- [Commits](docker/actions-toolkit@v0.1.0-beta.14...v0.1.0)

---
updated-dependencies:
- dependency-name: "@docker/actions-toolkit"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Signed-off-by: CrazyMax <[email protected]>

Signed-off-by: CrazyMax <[email protected]>

Signed-off-by: CrazyMax <[email protected]>

…ions-toolkit-0.1.0

Bump @docker/actions-toolkit from 0.1.0-beta.14 to 0.1.0

Bumps [docker/bake-action](https://github.com/docker/bake-action) from 2 to 3.
- [Release notes](https://github.com/docker/bake-action/releases)
- [Commits](docker/bake-action@v2...v3)

---
updated-dependencies:
- dependency-name: docker/bake-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Bumps [@docker/actions-toolkit](https://github.com/docker/actions-toolkit) from 0.1.0 to 0.3.0.
- [Release notes](https://github.com/docker/actions-toolkit/releases)
- [Commits](docker/actions-toolkit@v0.1.0...v0.3.0)

---
updated-dependencies:
- dependency-name: "@docker/actions-toolkit"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

…ake-action-3

Bump docker/bake-action from 2 to 3

…ions-toolkit-0.3.0

Bump @docker/actions-toolkit from 0.1.0 to 0.3.0