chore: add package.xml to gitignore

Author: r0b1n

.gitignore

@@ -19,6 +19,8 @@ mendixProject
 **/tests/testProject
 **/pluggableWidgets/**/artifacts
 **/gh-*/release-notes.txt
+packages/pluggableWidgets/*/src/package.xml
+!packages/pluggableWidgets/charts-web/src/package.xml
 
 **/automation/utils/**/parser/module/module.js
 **/automation/utils/**/parser/widget/widget.js