Apply GitHub Actions security best practices

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    cooldown:
+      default-days: 7

.github/workflows/check-signed-commits.yml

@@ -1,6 +1,9 @@
 name: Check signed commits in PR 
 on: pull_request_target
 
+permissions:
+  contents: read
+
 jobs:
   build:
     name: Check signed commits in PR 
@@ -9,5 +12,10 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        with:
+          egress-policy: audit
+
       - name: Check signed commits in PR
         uses: 1Password/check-signed-commits-action@main

.github/workflows/ok-to-test.yml

@@ -5,6 +5,9 @@ on:
   issue_comment:
     types: [created]
 
+permissions:
+  contents: read
+
 jobs:
   ok-to-test:
     runs-on: ubuntu-latest
@@ -14,8 +17,13 @@ jobs:
     # Only run for PRs, not issue comments
     if: ${{ github.event.issue.pull_request }}
     steps:
+    - name: Harden the runner (Audit all outbound calls)
+      uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+      with:
+        egress-policy: audit
+
     - name: Slash Command Dispatch
-      uses: peter-evans/slash-command-dispatch@v3
+      uses: peter-evans/slash-command-dispatch@f996d7b7aae9059759ac55e978cff76d91853301 # v3.0.2
       with:
         token: ${{ secrets.PERSONAL_ACCESS_TOKEN }} 
         reaction-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/validate.yml

@@ -11,6 +11,9 @@ on:
   repository_dispatch:
     types: [ ok-to-test-command ]
 
+permissions:
+  contents: read
+
 jobs:
 
   test-trusted:
@@ -22,9 +25,14 @@ jobs:
         python-version: ["3.10", "3.11", "3.12", "3.13"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@7f4fc3e22c37d6ff65e88745f38bd3157c663f7c # v4.9.1
         with:
           python-version: ${{ matrix.python-version }}
       - name: Integration Test
@@ -48,10 +56,15 @@ jobs:
     name: Lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
 
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@7f4fc3e22c37d6ff65e88745f38bd3157c663f7c # v4.9.1
         with:
           python-version: '3.x'
 
@@ -83,13 +96,18 @@ jobs:
     steps:
 
     # Check out merge commit
+    - name: Harden the runner (Audit all outbound calls)
+      uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+      with:
+        egress-policy: audit
+
     - name: Fork based /ok-to-test checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
       with:
         ref: ${{ github.event.client_payload.pull_request.head.sha }}
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@7f4fc3e22c37d6ff65e88745f38bd3157c663f7c # v4.9.1
       with:
         python-version: '3.x'
 
@@ -112,7 +130,7 @@ jobs:
         python example/example.py
 
     # Update check run called "integration-fork" on the forked PR
-    - uses: actions/github-script@v6
+    - uses: actions/github-script@d7906e4ad0b1822421a7e6a35d5ca353c962f410 # v6.4.1
       id: update-check-run
       if: ${{ always() }}
       env: