Remove "branchName" property on unmaintained branches

This will allow us to remove the branches themselves.

Author: greg0ire

.doctrine-project.json

@@ -23,73 +23,61 @@
     },
     {
       "name": "3.4",
-      "branchName": "3.4.x",
       "slug": "3.4",
       "maintained": false
     },
     {
       "name": "3.3",
-      "branchName": "3.3.x",
       "slug": "3.3",
       "maintained": false
     },
     {
       "name": "3.2",
-      "branchName": "3.2.x",
       "slug": "3.2",
       "maintained": false
     },
     {
       "name": "3.1",
-      "branchName": "3.1.x",
       "slug": "3.1",
       "maintained": false
     },
     {
       "name": "3.0",
-      "branchName": "3.0.x",
       "slug": "3.0",
       "maintained": false
     },
     {
       "name": "2.2",
-      "branchName": "2.2.x",
       "slug": "2.2",
       "maintained": true
     },
     {
       "name": "2.1",
-      "branchName": "2.1.x",
       "slug": "2.1",
       "maintained": false
     },
     {
       "name": "2.0",
-      "branchName": "2.0.x",
       "slug": "2.0",
       "maintained": false
     },
     {
       "name": "1.3",
-      "branchName": "1.3",
       "slug": "1.3",
       "maintained": false
     },
     {
       "name": "1.2",
-      "branchName": "1.2",
       "slug": "1.2",
       "maintained": false
     },
     {
       "name": "1.1",
-      "branchName": "1.1",
       "slug": "1.1",
       "maintained": false
     },
     {
       "name": "1.0",
-      "branchName": "1.0",
       "slug": "1.0",
       "maintained": false
     }