Rust: add upgrades property in qlpack.yml

Author: Paolo Tranquilli

rust/ql/lib/qlpack.yml

@@ -4,6 +4,7 @@ groups: rust
 extractor: rust
 dbscheme: rust.dbscheme
 library: true
+upgrades: upgrades
 dependencies:
   codeql/controlflow: ${workspace}
   codeql/dataflow: ${workspace}