ci: read the Context7 error field with jq

Same fix as review feedback on solid-objects-js#65. The too-early check matched
the exact string "error":"too-early", so valid JSON with other
spacing, such as {"error": "too-early"}, would fail the job instead
of skipping. Read the field with jq. On four sample bodies, grep
missed the spaced form and jq skipped it, and both still fail on
another error and on a body that is not JSON. Against the live API
the workflow script still exits 0 with the notice.

Author: cardmagic

.github/workflows/context7-refresh.yml

@@ -33,7 +33,7 @@ jobs:
           if [ "$status" = "200" ]; then
             exit 0
           fi
-          if [ "$status" = "400" ] && grep -q '"error":"too-early"' response.json; then
+          if [ "$status" = "400" ] && jq -e '.error == "too-early"' response.json > /dev/null; then
             echo "::notice::Context7 refreshed $LIBRARY_NAME recently, so it skipped this refresh."
             exit 0
           fi