Add GitHub token permissions for workflows

Follows rubocop/rubocop#10947

Author: Earlopain

.github/workflows/linting.yml

@@ -1,11 +1,19 @@
 name: Linting
 on:
   - pull_request
+
+permissions:  # added using https://github.com/step-security/secure-workflows
+  contents: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
+
 jobs:
   yamllint:
+    permissions:
+      contents: read  # for actions/checkout to fetch code
+      pull-requests: write  # for karancode/yamllint-github-action to post comments on PRs
     name: Yamllint
     runs-on: ubuntu-latest
     steps:

.github/workflows/spell_checking.yml

@@ -2,6 +2,9 @@ name: Spell Checking
 
 on: [pull_request]
 
+permissions:  # added using https://github.com/step-security/secure-workflows
+  contents: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true

.github/workflows/test.yml

@@ -7,6 +7,9 @@ on:
   pull_request:
   workflow_dispatch:
 
+permissions:  # added using https://github.com/step-security/secure-workflows
+  contents: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true