Bump actions/checkout from 2 to 3 (#320)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3)

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

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

.github/workflows/downstream.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
             python-version: "3.8"
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - name: Install project dependencies
@@ -53,7 +53,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - name: Run pre-commit
         uses: pre-commit/[email protected]
@@ -73,7 +73,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - uses: conda-incubator/setup-miniconda@v2
@@ -95,7 +95,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - name: Install Dependencies
@@ -111,7 +111,7 @@ jobs:
     timeout-minutes: 20
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
         with:
@@ -127,7 +127,7 @@ jobs:
     timeout-minutes: 20
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - name: Install the Python dependencies
@@ -145,7 +145,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 20
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - name: Build SDist
@@ -186,6 +186,6 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - uses: jupyterlab/maintainer-tools/.github/actions/check-links@v1