feat(@angular/cli): added *.sublime-workspace to gitignore blueprint (#4698)

According to https://www.sublimetext.com/docs/3/projects.html :
"Projects in Sublime Text are made up of two files: the .sublime-project
file, which contains the project definition, and the .sublime-workspace
file, which contains user specific data, such as the open files and the
modifications to each.

As a general rule, the .sublime-project file would be checked into
version control, while the .sublime-workspace file would not."

Author: LJNielsenDk

packages/@angular/cli/blueprints/ng2/files/gitignore

@@ -14,6 +14,7 @@
 .c9/
 *.launch
 .settings/
+*.sublime-workspace
 
 # IDE - VSCode
 .vscode/*