[PR Workflow] Add TypeSpec label if appropriate files are changed

[konrad-jamrozik]

As in title. We need this for several reasons, including:

• [PR Workflow] Use more labels for new TypeSpec identification #7216
• [PR Workflow] Automatic ARM sign-off for TypeSpec-based PRs  #7352

Implementation-wise, we want to implement this in openapi-alps PR summary task (recent example PR touching relevant code files), following rules as expressed in this PR:

• https://github.com/Azure/azure-rest-api-specs/pull/26542/files#diff-fc796b019795da5d3269d452fcdb1827ca9c8789a41f2e2dc1551f70b8f36878

description:
- if:
  - payloadType: Pull_Request
  then:
  - if:
    - filesMatchPattern: # any files, not necessarily all
        pattern: specification/.*(\.tsp|tspconfig.yaml)
    then:
    - addLabel:
        label: TypeSpec

Note that the above-given PR doesn't work as expected because the filesMatchPattern selector requires for all files to match the pattern [1]. We want to ad the label when any files match the pattern.

One situation to consider is: what if given PR has both OpenAPI specs created by hand, and also generated from TypeSpec? In such case we also add the TypeSpec label. The assumption here is that such cases should be very rare and can be handled manually, while automation can approximate such PR to being TypeSpec-only PRs.

Related work:

• [PR Workflow] Update REST API PR labeling bot for TypeSpec rename #5917

[1]:
source of filesMatchPattern
doc for filesMatchPattern
issue we filed

[konrad-jamrozik]

Closing as implemented and deployed. For example, this PR got the TypeSpec label:

• [WIP] MFE Indexes tsp base template azure-rest-api-specs#26941

You can see a call to the newly modified processTypeSpec function in this build log.