Bump actions/checkout from 2.3.4 to 2.4.0 (#1052)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.4 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.4...v2.4.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/changelog.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2.3.4
+    - uses: actions/checkout@v2.4.0
 
     - name: Grep CHANGES.md for PR number
       if: contains(github.event.pull_request.labels.*.name, 'skip news') != true

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
         os: [macOS-latest, windows-latest]
 
     steps:
-    - uses: actions/checkout@v2.3.4
+    - uses: actions/checkout@v2.4.0
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2.2.2

.github/workflows/ci_ubuntu.yml

@@ -25,7 +25,7 @@ jobs:
         os: [ubuntu-latest]
 
     steps:
-    - uses: actions/checkout@v2.3.4
+    - uses: actions/checkout@v2.4.0
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2.2.2

.github/workflows/doc_build.yml

@@ -9,7 +9,7 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2.3.4
+    - uses: actions/checkout@v2.4.0
 
     - name: Set up latest Python
       uses: actions/setup-python@v2.2.2

.github/workflows/docker_upload.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2.3.4
+        uses: actions/checkout@v2.4.0
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1

.github/workflows/pypi_upload.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2.3.4
+    - uses: actions/checkout@v2.4.0
 
     - name: Set up Python
       uses: actions/setup-python@v2.2.2