Fix Danger plist warning being triggered on every PR (#489)

The warning "Plist changed, don't forget to localize your plist values" was being incorrectly shown on every PR, even when no plist file was modified. Fixed two bugs in the Dangerfile:
1. Inverted condition: Changed from `if !is_plist_change` to `if is_plist_change` so the warning only fires when a plist is actually modified
2. Wrong file path: Changed from checking `"ProjectName/Info.plist"` to `"Source/Info.plist"` to match the actual project structure

Author: Zandor300

Dangerfile

@@ -31,9 +31,9 @@ if has_app_changes && !has_test_changes && git.lines_of_code > 10
 end
 
 # Info.plist file shouldn't change often. Leave warning if it changes.
-is_plist_change = git.modified_files.sort == ["ProjectName/Info.plist"].sort
+is_plist_change = git.modified_files.include?("Source/Info.plist")
 
-if !is_plist_change
+if is_plist_change
   warn "Plist changed, don't forget to localize your plist values"
 end