fix plrust package var interpolation

Author: olirice

ansible/tasks/postgres-extensions/30-plrust.yml

@@ -39,7 +39,7 @@
 
 - name: plrust - install plrust
   ansible.builtin.apt:
-    deb: "https://github.com/tcdi/plrust/releases/download/v{{ plrust_release }/plrust-trusted-{ plrust_release }_{{ plrust_language_version }}-debian-pg{{ postgresql_major }}-{ platform }}.deb"
+    deb: "https://github.com/tcdi/plrust/releases/download/v{{ plrust_release }/plrust-trusted-{{ plrust_release }}_{{ plrust_language_version }}-debian-pg{{ postgresql_major }}-{{ platform }}.deb"
 
 - name: plrust - install rust
   become: yes