GHA: Specify "read" permission

as recommended by CodeQL

Change-Id: If1a96af491181ad410ba3b75722c630293a23d8f
Reviewed-on: https://review.couchbase.org/c/couchbase-jvm-clients/+/229388
Reviewed-by: David Nault <[email protected]>
Tested-by: David Nault <[email protected]>

Author: dnault

.github/workflows/integration-test.yml

@@ -40,6 +40,8 @@ jobs:
 #            java-distribution: 'oracle'
 #            java-version: '17'
 
+    permissions:
+      contents: read
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4