feat(core-step-tracker): make full width, add bg colour options

[marcod1419]

See: #731

This makes step tracker full width while also making the background colour grey by default. It includes a new backgroundColour prop to switch the background to white if preferred.

[TDSBot]

Changes:
 - @tds/core-flex-grid: 2.3.0 => 2.3.1
 - @tds/core-notification: 1.2.3 => 1.2.4
 - @tds/core-price-lockup: 1.0.2 => 1.0.3
 - @tds/core-step-tracker: 2.0.3 => 2.1.0


🤔 If this is not what you expected, ensure that your commit messages follow the Conventional Commits specification (https://conventionalcommits.org) and try again.

🚀 Please paste the entire output of this task into the body of your Pull Request so that a maintainer can verify before merging/publishing.

[TDSBot]

Changes:
 - @tds/core-flex-grid: 2.3.0 => 2.3.1
 - @tds/core-notification: 1.2.3 => 1.2.4
 - @tds/core-price-lockup: 1.0.2 => 1.0.3
 - @tds/core-step-tracker: 2.0.3 => 2.1.0


🤔 If this is not what you expected, ensure that your commit messages follow the Conventional Commits specification (https://conventionalcommits.org) and try again.

🚀 Please paste the entire output of this task into the body of your Pull Request so that a maintainer can verify before merging/publishing.

[jraff]

I think this should be a breaking change.

[jraff]

It looks like core-text was downgraded.

[marcod1419]

Weird. Will fix.

[jraff]

Should we use $color-white here?

[marcod1419]

Sure.

[marcod1419]

@jraff It is. Just forgot to add the indicator! I'll do that now.

[TDSBot]

Changes:
 - @tds/core-expand-collapse: 1.2.1 => 1.2.2
 - @tds/core-flex-grid: 2.3.0 => 2.3.1
 - @tds/core-hairline-divider: 1.0.0 => 1.0.1
 - @tds/core-notification: 1.2.3 => 1.2.4
 - @tds/core-price-lockup: 1.0.2 => 1.0.3
 - @tds/core-step-tracker: 2.0.3 => 3.0.0


🤔 If this is not what you expected, ensure that your commit messages follow the Conventional Commits specification (https://conventionalcommits.org) and try again.

🚀 Please paste the entire output of this task into the body of your Pull Request so that a maintainer can verify before merging/publishing.

[TDSBot]

Changes:
 - @tds/core-expand-collapse: 1.2.1 => 1.2.2
 - @tds/core-flex-grid: 2.3.0 => 2.3.1
 - @tds/core-hairline-divider: 1.0.0 => 1.0.1
 - @tds/core-notification: 1.2.3 => 1.2.4
 - @tds/core-price-lockup: 1.0.2 => 1.0.3
 - @tds/core-step-tracker: 2.0.3 => 3.0.0


🤔 If this is not what you expected, ensure that your commit messages follow the Conventional Commits specification (https://conventionalcommits.org) and try again.

🚀 Please paste the entire output of this task into the body of your Pull Request so that a maintainer can verify before merging/publishing.

[jraff]

👍