chore(deps): update actions/checkout action to v4

Author: renovate-bot

.github/workflows/build.yml

@@ -8,7 +8,7 @@ jobs:
   compile:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Setup Node.js
       uses: actions/setup-node@v1
       with:

.github/workflows/buildpack-integration-test.yml

@@ -91,7 +91,7 @@ jobs:
           GITHUB_CONTEXT: ${{ toJSON(github) }}
         run: echo "$GITHUB_CONTEXT"
       - name: Checkout functions-framework-conformance
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: 'GoogleCloudPlatform/functions-framework-conformance'
           ref: ${{ inputs.conformance-action-version }}
@@ -157,7 +157,7 @@ jobs:
         run: echo "$HOME/go/bin" >> $GITHUB_PATH
       - name: Check out repository
         if: ${{ matrix.builder-source }}
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Prerun script
         if: ${{ matrix.builder-source && inputs.prerun }}
         run: bash -x ${{ inputs.prerun }}

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
   run-conformance:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - uses: actions/setup-go@v2
       with:

.github/workflows/unit.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Check out repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Set up Go
         uses: actions/setup-go@v2