Grant pull-requests write permission to PR comment workflows (#390)

The PR workflows call thollander/actions-comment-pull-request to post
review/build/label comments, but declare no permissions block, so they
inherit the repository's default read-only GITHUB_TOKEN and fail with
"Resource not accessible by integration" (e.g. the "Pull Request Approved"
workflow when a PR is approved).

Add a permissions block (contents: read, pull-requests: write) to
pr-review.yml, maven-pr.yml and gradle-pr.yml so the comment steps can
create/update comments.

Co-authored-by: joseegarcia <jose.garcia@disashop.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

.github/workflows/gradle-pr.yml

@@ -6,6 +6,10 @@ on:
 
 concurrency: pr-gradle-${{ github.event.pull_request.id }}
 
+permissions:
+  contents: read
+  pull-requests: write
+
 jobs:
   check-version:
     runs-on: ubuntu-latest

.github/workflows/maven-pr.yml

@@ -6,6 +6,10 @@ on:
 
 concurrency: pr-${{ github.event.pull_request.id }}
 
+permissions:
+  contents: read
+  pull-requests: write
+
 jobs:
   check-version:
     runs-on: ubuntu-latest

.github/workflows/pr-review.yml

@@ -6,6 +6,10 @@ on:
 
 concurrency: pr-${{ github.event.pull_request.id }}
 
+permissions:
+  contents: read
+  pull-requests: write
+
 jobs:
   check-labels:
     runs-on: ubuntu-latest