Add rules and test for draft 3 to 4 schema keyword (#26)

Author: suprith-hub

rules/from-draft3/to-draft4/009-schema.json

@@ -0,0 +1,10 @@
+{
+    "vocabulary": "core",
+    "condition": [
+        { "operation": "has-key", "path": [], "value": "$schema" },
+        { "operation": "match-pattern", "path": [ "$schema" ], "value": "^http[s]?://json-schema.org/draft-03/schema[#]?$" }
+    ],
+    "transform": [
+        { "operation": "replace", "path": [ "$schema" ], "value": "http://json-schema.org/draft-04/schema#" }
+    ]
+}

test/from-draft3/to-draft4/schema.json

@@ -0,0 +1,91 @@
+[
+    {
+        "title": "Simple matching schema",
+        "from": {
+            "$schema": "https://json-schema.org/draft-03/schema"
+        },
+        "to": {
+            "$schema": "https://json-schema.org/draft-04/schema"
+        }
+    },
+    {
+        "name": "$schema with https scheme",
+        "from": {
+          "$schema": "http://json-schema.org/draft-03/schema#"
+        },
+        "to": {
+          "$schema": "http://json-schema.org/draft-04/schema#"
+        }
+    },
+    {
+        "name": "$schema without an empty fragment",
+        "from": {
+          "$schema": "http://json-schema.org/draft-03/schema"
+        },
+        "to": {
+          "$schema": "http://json-schema.org/draft-04/schema#"
+        }
+    },
+    {
+        "title": "Simple non matching schema",
+        "from": {
+            "$schema": "https://json-schema.org/draft/2020-12/schema"
+        },
+        "to": {
+            "$schema": "https://json-schema.org/draft/2020-12/schema"
+        }
+    },
+    {
+        "title": "Nested matching schema",
+        "from": {
+            "$schema": "https://json-schema.org/draft-03/schema",
+            "properties": {
+                "foo": {
+                    "$schema": "https://json-schema.org/draft-03/schema"
+                }
+            }
+        },
+        "to": {
+            "$schema": "https://json-schema.org/draft-04/schema",
+            "properties": {
+                "foo": {
+                    "$schema": "https://json-schema.org/draft-04/schema"
+                }
+            }
+        }
+    },
+    {
+        "title": "Nested half matching schema",
+        "from": {
+            "$schema": "https://json-schema.org/draft/2020-12/schema",
+            "properties": {
+                "foo": {
+                    "$schema": "https://json-schema.org/draft-03/schema"
+                }
+            }
+        },
+        "to": {
+            "$schema": "https://json-schema.org/draft/2020-12/schema",
+            "properties": {
+                "foo": {
+                    "$schema": "https://json-schema.org/draft-04/schema"
+                }
+            }
+        }
+    },
+    {
+        "title": "$schema inside unknown keyword",
+        "from": {
+            "$schema": "https://json-schema.org/draft-03/schema",
+            "foo": {
+                "$schema": "https://json-schema.org/draft-03/schema"
+            }
+        },
+        "to": {
+            "$schema": "https://json-schema.org/draft-04/schema",
+            "foo": {
+                "$schema": "https://json-schema.org/draft-03/schema"
+            }
+        }
+    }
+]

test/from-draft7/to-2019-09/schema.json

@@ -20,16 +20,16 @@
     {
         "title": "Nested matching schema",
         "from": {
-            "$schema": "http://json-schema.org/draft-07/schema#",
-            "definitions": {
+            "$schema": "https://json-schema.org/draft-07/schema",
+            "properties": {
                 "foo": {
                     "$schema": "http://json-schema.org/draft-07/schema#"
                 }
             }
         },
         "to": {
             "$schema": "https://json-schema.org/draft/2019-09/schema",
-            "definitions": {
+            "properties": {
                 "foo": {
                     "$schema": "https://json-schema.org/draft/2019-09/schema"
                 }
@@ -41,6 +41,7 @@
         "from": {
             "$schema": "https://json-schema.org/draft/2019-09/schema",
             "definitions": {
+
                 "foo": {
                     "$schema": "http://json-schema.org/draft-07/schema#"
                 }
@@ -71,3 +72,5 @@
         }
     }
 ]
+
+