fix(@angular-devkit/build-angular): add pattern validations for browserTarget and serverTarget

Author: alan-agius4

packages/angular_devkit/build_angular/src/app-shell/schema.json

@@ -6,11 +6,13 @@
   "properties": {
     "browserTarget": {
       "type": "string",
-      "description": "Target to build."
+      "description": "Target to build.",
+      "pattern": "^[^:\\s]+:[^:\\s]+(:[^\\s]+)?$"
     },
     "serverTarget": {
       "type": "string",
-      "description": "Server target to use for rendering the app shell."
+      "description": "Server target to use for rendering the app shell.",
+      "pattern": "^[^:\\s]+:[^:\\s]+(:[^\\s]+)?$"
     },
     "appModuleBundle": {
       "type": "string",

packages/angular_devkit/build_angular/src/dev-server/schema.json

@@ -7,7 +7,7 @@
     "browserTarget": {
       "type": "string",
       "description": "Target to serve.",
-      "pattern": ".+:.+(:.+)?"
+      "pattern": "^[^:\\s]+:[^:\\s]+(:[^\\s]+)?$"
     },
     "port": {
       "type": "number",

packages/angular_devkit/build_angular/src/extract-i18n/schema.json

@@ -6,7 +6,8 @@
   "properties": {
     "browserTarget": {
       "type": "string",
-      "description": "Target to extract from."
+      "description": "Target to extract from.",
+      "pattern": "^[^:\\s]+:[^:\\s]+(:[^\\s]+)?$"
     },
     "format": {
       "type": "string",

packages/angular_devkit/build_angular/src/protractor/schema.json

@@ -10,7 +10,8 @@
     },
     "devServerTarget": {
       "type": "string",
-      "description": "Dev server target to run tests against."
+      "description": "Dev server target to run tests against.",
+      "pattern": "^([^:\\s]+:[^:\\s]+(:[^\\s]+)?)?$"
     },
     "specs": {
       "type": "array",