ci: validate schema in the same workflow as other checks (#373)

There's no real advantage to doing the validation only when the schema
file has changed since it's very quick and the current workflow is set
to trigger whenever a pull request is edited which includes the PR
title, description, etc

Signed-off-by: Gareth Jones <[email protected]>

Author: G-Rath

.github/workflows/checks.yml

@@ -76,3 +76,17 @@ jobs:
           git diff --name-only \
             | xargs -I '{}' bash -c \
               'echo "::error file={}::This needs to be regenerated by running \`python3 ./scripts/update-ecosystems-lists.py\`" && false'
+
+  validate-osv-schema:
+    name: Validate OSV Schema
+    permissions:
+      contents: read
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Validate OSV Schema
+        uses: dsanders11/json-schema-validate-action@ec60131eddf6f51ed0c737fdcd28616ae1a0e564 # v1.2.0
+        with:
+          # https://github.com/marketplace/actions/json-schema-validate#validating-schema
+          schema: json-schema
+          files: validation/schema.json