Update actions/checkout action to v4 (#1350)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ jobs:
   javascript-tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 20.8.1
@@ -37,11 +37,11 @@ jobs:
     timeout-minutes: 60
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 20
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
         with:
           repository: "mitodl/ocw-hugo-projects"
           ref: "main"

.github/workflows/deploy.yml

@@ -15,7 +15,7 @@ jobs:
           known_hosts: ${{ secrets.KNOWN_HOSTS }}
           if_key_exists: replace
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
       - name: Setup Node
         uses: actions/setup-node@v3
         with:
@@ -38,7 +38,7 @@ jobs:
         run: (cd ..; git clone [email protected]:ocw-content-rc/15.s21-january-iap-2014.git ocw-course)
 
       - name: Clone ocw-hugo-projects for config
-        uses: actions/checkout@v3
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
         with:
           repository: "mitodl/ocw-hugo-projects"
           ref: "main"
@@ -148,7 +148,7 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ github.event_name == 'pull_request' }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
       - name: Setup Node
         uses: actions/setup-node@v3
         with: