[resource/host] Change type of host.cpu.stepping to string

[ChrsMark]

Fixes #664

Changes

This PR changes the type of host.cpu.stepping to string in order to cover values like r1p1 as described at #664.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• CHANGELOG.md updated for non-trivial changes.
• schema-next.yaml updated with changes to existing conventions.
  ⚠️ this cannot be expressed in a schema translation at the moment, see host.cpu.stepping should be string #664

[jsuereth]

Ok with this change mostly assuming this is a rare/new field that isn't used much.

If someone can confirm this field is little used in the wild, that'd be ideal.

[mx-psi]

If someone can confirm this field is little used in the wild, that'd be ideal.

From a Github search, only the OpenTelemetry Collector resource detection processor system detector supports this attribute. It is not enabled by default and we have done similar changes to other host.cpu fields in the past without much complaint, so I think it's safe to assume it's not widely used.

[ChrsMark]

I guess we need to update this PR to use the new changelog structure: https://github.com/open-telemetry/semantic-conventions/blob/main/CONTRIBUTING.md#adding-a-changelog-entry. @joaopgrassi is that correct?

[joaopgrassi]

I guess we need to update this PR to use the new changelog structure: main/CONTRIBUTING.md#adding-a-changelog-entry. @joaopgrassi is that correct?

@ChrsMark yes that would be great, thanks! Then we are ready to merge :)

[ChrsMark]

@joaopgrassi done cdbe5c2