ci: pin js-yaml install

Use an explicit js-yaml version in the reusable test workflow so CI does
not silently pick up parser behavior changes from future npm releases.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

.github/workflows/.test.yml

@@ -56,7 +56,7 @@ jobs:
       -
         name: Deps
         run: |
-          npm install js-yaml
+          npm install --no-save js-yaml@5.1.0
       -
         name: Set outputs
         id: set