fix(@angular/cli): add ng-packagr builder schema in IDE schema

(cherry picked from commit 5f8155d)

Author: alan-agius4

packages/angular/cli/lib/config/schema.json

@@ -492,7 +492,8 @@
                       "@angular-devkit/build-angular:karma",
                       "@angular-devkit/build-angular:protractor",
                       "@angular-devkit/build-angular:server",
-                      "@angular-devkit/build-angular:tslint"
+                      "@angular-devkit/build-angular:tslint",
+                      "@angular-devkit/build-angular:ng-packagr"
                     ]
                   }
                 },
@@ -598,6 +599,17 @@
                   "additionalProperties": { "$ref": "#/definitions/targetOptions/definitions/tslint" }
                 }
               }
+            },
+            {
+              "type": "object",
+              "properties": {
+                "builder": { "const": "@angular-devkit/build-angular:ng-packagr" },
+                "options": { "$ref": "#/definitions/targetOptions/definitions/ngPackagr" },
+                "configurations": {
+                  "type": "object",
+                  "additionalProperties": { "$ref": "#/definitions/targetOptions/definitions/ngPackagr" }
+                }
+              }
             }
           ]
         }
@@ -2101,6 +2113,29 @@
             }
           },
           "additionalProperties": false
+        },
+        "ngPackagr": {
+          "description": "ng-packagr target options for Build Architect. Use to build library projects.",
+          "type": "object",
+          "properties": {
+            "project": {
+              "type": "string",
+              "description": "The file path for the ng-packagr configuration file, relative to the current workspace."
+            },
+            "tsConfig": {
+              "type": "string",
+              "description": "The full path for the TypeScript configuration file, relative to the current workspace."
+            },
+            "watch": {
+              "type": "boolean",
+              "description": "Run build when files change.",
+              "default": false
+            }
+          },
+          "additionalProperties": false,
+          "required": [
+            "project"
+          ]
         }
       }
     },