Update maintained versions (#881)

Author: GromNaN

.doctrine-project.json

@@ -4,16 +4,28 @@
     "slug": "doctrine-mongodb-bundle",
     "versions": [
         {
-            "name": "5.1",
-            "branchName": "5.1.x",
+            "name": "5.3",
+            "branchName": "5.3.x",
             "slug": "latest",
             "upcoming": true
         },
+        {
+            "name": "5.2",
+            "branchName": "5.2.x",
+            "slug": "5.2",
+            "current": true
+        },
+        {
+            "name": "5.1",
+            "branchName": "5.1.x",
+            "slug": "5.1",
+            "maintained": false
+        },
         {
             "name": "5.0",
             "branchName": "5.0.x",
             "slug": "5.0",
-            "current": true
+            "maintained": false
         },
         {
             "name": "4.7",