feat(devservices): Add devservices ci validation job (#6716)

This validation job will only run if files are changed in the
`devservices/` directory or the `.github/workflows/ci.yml` has been
changed. It will ensure that the config files that live in the snuba
devservices directory actually work, preventing potential breakages for
devservices across repos that depend on snuba if invalid configs are
merged.

Composite action used:
https://github.com/getsentry/action-validate-devservices-config

.github/file-filters.yml

@@ -8,3 +8,7 @@ api_changes:
   - "snuba/cli/devserver.py"
   - "rust_snuba/src/processors/*"
   - "snuba/datasets/processors/*"
+
+devservices_changes:
+  - 'devservices/**'
+  - '.github/workflows/ci.yml'

.github/workflows/ci.yml

@@ -13,6 +13,7 @@ jobs:
     # Map a step output to a job output
     outputs:
       api_changes: ${{ steps.changes.outputs.api_changes }}
+      devservices_changes: ${{ steps.changes.outputs.devservices_changes }}
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v2
 
@@ -486,3 +487,15 @@ jobs:
           # finally, nightly
           docker tag ${IMAGE_URL} getsentry/snuba:nightly
           docker push getsentry/snuba:nightly
+
+  validate-devservices-config:
+    runs-on: ubuntu-24.04
+    needs: files-changed
+    if: ${{ needs.files-changed.outputs.devservices_changes == 'true' }}
+    steps:
+    - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+      name: Checkout repository
+    - uses: getsentry/action-validate-devservices-config@6477ef1e9c96e456bfad726006e731f89fcd81db
+      name: Validate devservices config
+      with:
+        requirements-file-path: requirements.txt