add json lint actions

.github/workflows/jsonlint.yml

@@ -0,0 +1,24 @@
+name: Check Json format
+
+on: [push, pull_request]
+
+jobs:
+  jsonlint:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/[email protected]
+    - name: Get Diff Action
+      uses: technote-space/[email protected]
+      with:
+        SUFFIX_FILTER: .json
+    - name: Install node
+      run: |
+        sudo apt install nodejs
+    - name: Install jsonlint
+      run: |
+        sudo npm install -g jsonlint
+    - name: Lint with jsonlint
+      run: |
+        for file in ${{ env.GIT_DIFF }}; do npx jsonlint $file; done
+      if: env.GIT_DIFF