add json check

.github/json_check.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+JSON_DIR=$1
+RC=0
+
+for JSON_FILE in $(ls "$JSON_DIR"); do
+    jq type 1>/dev/null < "$JSON_DIR/$JSON_FILE"
+    if [ $? -gt 0 ]; then
+        echo "Error in file: $JSON_DIR/$JSON_FILE"
+        RC=1
+    fi
+done
+
+exit "$RC"

.github/workflows/lint.yml

@@ -0,0 +1,18 @@
+---
+name: Lint
+
+on:
+  pull_request:
+    paths:
+      - "secjson/**/**"
+
+jobs:
+  build:
+    name: JSON lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+      - name: Check JSON files
+        run: .github/json_check.sh secjson