Add blog to project schema

schema/project.json

@@ -75,6 +75,11 @@
       ],
       "type": "string"
     },
+    "blog": {
+      "description": "Project's blog.",
+      "format": "uri",
+      "type": ["string"]
+    },
     "demo": {
       "description": "Optional URL to the project demo.",
       "format": "uri",

schema/tests/data/project/negative/blog-none.yaml

@@ -0,0 +1,16 @@
+audience: breaker
+blog:
+leaders:
+  - github: leader-1-github
+    name: Leader 1 Name
+  - github: leader-2-github
+    name: Leader 2 Name
+level: 2
+name: OWASP Incubator Code Project
+pitch: A very brief, one-line description of your project
+
+tags:
+  - example-tag-1
+  - example-tag-2
+  - example-tag-3
+type: code

schema/tests/data/project/positive/optional-properties.yaml

@@ -1,4 +1,5 @@
 audience: breaker
+blog: https://blog.projec.com
 demo: https://some-demo-url.com
 downloads:
   - https://abc.com/download1

schema/tests/project_test.py

@@ -29,6 +29,7 @@ def test_positive(project_schema):
         ),
         ("audience-empty.yaml", "'' is not one of ['breaker', 'builder', 'defender']"),
         ("audience-missing.yaml", "'audience' is a required property"),
+        ("blog-none.yaml", "None is not of type 'string'"),
         ("demo-none.yaml", "None is not of type 'string'"),
         ("downloads-empty.yaml", "[] should be non-empty"),
         (