Ignore .vscode/ in Git

This is the directory used by Visual Studio Code for customized
workspace preferences.

Change-Id: I8bf38a5b3b8a4fe89e6b0c611e8dcb4b9a9f3302

.gitignore

@@ -45,6 +45,9 @@ contrib/dev/vagrant/storage/
 .project
 .pydevproject
 
+# Files generated by Visual Studio Code
+.vscode/
+
 # Files created by reno build
 releasenotes/build