add vega-lite diagram (#574)

added vega-lite diagrams
Update CHANGELOG.md

Co-authored-by: mrdrogdrog <mr.drogdrog@gmail.com>

src/components/editor/editorTestContent.ts

@@ -9,6 +9,52 @@ opengraph:
 # Embedding demo
 [TOC]
 
+## Vega-Lite
+
+\`\`\`vega-lite
+
+
+{
+  "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
+  "description": "Reproducing http://robslink.com/SAS/democd91/pyramid_pie.htm",
+  "data": {
+    "values": [
+      {"category": "Sky", "value": 75, "order": 3},
+      {"category": "Shady side of a pyramid", "value": 10, "order": 1},
+      {"category": "Sunny side of a pyramid", "value": 15, "order": 2}
+    ]
+  },
+  "mark": {"type": "arc", "outerRadius": 80},
+  "encoding": {
+    "theta": {
+      "field": "value", "type": "quantitative",
+      "scale": {"range": [2.35619449, 8.639379797]},
+      "stack": true
+    },
+    "color": {
+      "field": "category", "type": "nominal",
+      "scale": {
+        "domain": ["Sky", "Shady side of a pyramid", "Sunny side of a pyramid"],
+        "range": ["#416D9D", "#674028", "#DEAC58"]
+      },
+      "legend": {
+        "orient": "none",
+        "title": null,
+        "columns": 1,
+        "legendX": 200,
+        "legendY": 80
+      }
+    },
+    "order": {
+      "field": "order"
+    }
+  },
+  "view": {"stroke": null}
+}
+
+
+\`\`\`
+
 ## GraphViz
 
 \`\`\`graphviz