Update .gitignore

added .DS_Store to gitignore to prevent these macOS files from being added automatically

Author: rishabh-ghosh24

.gitignore

@@ -3,4 +3,4 @@ shared-assets/bastion-py-script/.oci/
 shared-assets/bastion-py-script/temp/
 temp/
 app-dev/app-integration-and-automation/oracle-integration-cloud/01-oic-connectivity-agent/README_tmp.html
-.DS_Store
+.DS_Store