fix(templating): allow category field (#25075)

lib/util/template/index.ts

@@ -72,6 +72,7 @@ export const exposedConfigOptions = [
 export const allowedFields = {
   baseBranch: 'The baseBranch for this branch/PR',
   body: 'The body of the release notes',
+  category: 'The category of the manager of the dependency being updated',
   currentValue: 'The extracted current value of the dependency being updated',
   currentVersion:
     'The version that would be currently installed. For example, if currentValue is ^3.0.0 then currentVersion might be 3.1.0.',