feat(odoo_repos): update default version variable in README.md

- Changed default version variable from `odoo_revision` to `odoo_version` for consistency
- Improves clarity and aligns with existing variable naming conventions in Odoo roles

Author: janikvonrotz

roles/odoo_repos/README.md

@@ -22,7 +22,7 @@ odoo_repos:
     version: 16.0 # default: "{{ odoo_revision }}"
   - path: addons/mint-system-server-tools
     url: [email protected]:Mint-System/Odoo-Apps-Server-Tools.git
-    version: 17.0-mig-session_db # default: "{{ odoo_revision }}"
+    version: 17.0-mig-session_db # default: "{{ odoo_version }}"
     single_branch: false
   - path: addons/oca-partner-contact
     url: [email protected]:OCA/partner-contact.git