Bump actions/checkout from 2.3.4 to 2.4.0 (#113)

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>

.github/workflows/binderbadge.yaml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout PR
-        uses: actions/checkout@v2.3.4
+        uses: actions/checkout@v2.4.0
 
       - name: Comment on PR with Binder link
         uses: actions/github-script@v4.1

.github/workflows/cron.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2.3.4
+        uses: actions/checkout@v2.4.0
 
       - name: Setup Miniconda
         uses: conda-incubator/setup-miniconda@v2.1.1

.github/workflows/main.yaml

@@ -10,7 +10,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.3.4
+      - uses: actions/checkout@v2.4.0
       - uses: actions/setup-python@v2.2.2
       - uses: pre-commit/action@v2.0.3
 
@@ -23,7 +23,7 @@ jobs:
         CONDA_ENV: [3.7, 3.8, 3.9, upstream]
     steps:
       - name: Checkout
-        uses: actions/checkout@v2.3.4
+        uses: actions/checkout@v2.4.0
 
       - name: Setup Miniconda
         uses: conda-incubator/setup-miniconda@v2.1.1

.github/workflows/pypipublish.yaml

@@ -8,7 +8,7 @@ jobs:
   deploy:
     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
         with: