feat(cerbos): Add principal schema definition

Author: jonphipps

.gitignore

@@ -43,3 +43,4 @@ settings.json
 playwright-report
 .env.local
 /conf.yaml
+fixtures/

cerbos/_schemas/principal.json

@@ -0,0 +1,53 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "object",
+  "properties": {
+    "id": {
+      "type": "string"
+    },
+    "roles": {
+      "type": "array",
+      "items": {
+        "type": "string"
+      }
+    },
+    "attributes": {
+      "type": "object",
+      "properties": {
+        "namespaces": {
+          "type": "object",
+          "patternProperties": {
+            ".*": {
+              "type": "string"
+            }
+          },
+          "additionalProperties": false
+        },
+        "sites": {
+          "type": "object",
+          "patternProperties": {
+            ".*": {
+              "type": "string"
+            }
+          },
+          "additionalProperties": false
+        },
+        "languages": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "github_username": {
+          "type": "string"
+        },
+        "email": {
+          "type": "string"
+        }
+      },
+      "additionalProperties": true
+    }
+  },
+  "required": ["id", "roles"],
+  "additionalProperties": true
+}