fix(@angular/cli): update regex to validate the project-name

Author: harshlakhara

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

@@ -23,7 +23,7 @@
     "projects": {
       "type": "object",
       "patternProperties": {
-        "^(?:@[a-zA-Z0-9_-]+/)?[a-zA-Z0-9_-]+$": {
+        "^(?:@[a-zA-Z0-9._-]+/)?[a-zA-Z0-9._-]+$": {
           "$ref": "#/definitions/project"
         }
       },