Bump actions/checkout from 2 to 3

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](https://github.com/actions/checkout/compare/v2...v3)

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

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

.github/workflows/CD.yml

@@ -18,7 +18,7 @@ jobs:
     environment: package
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Cache conda
         uses: actions/cache@v3
         with:

.github/workflows/deploy-website.yml

@@ -15,7 +15,7 @@ jobs:
       run:
         working-directory: website
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
           node-version: 14.x
@@ -51,7 +51,7 @@ jobs:
       run:
         working-directory: website
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
           node-version: 14.x

.github/workflows/python-package.yml

@@ -19,7 +19,7 @@ jobs:
         python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
@@ -87,7 +87,7 @@ jobs:
   #   runs-on: ubuntu-latest
 
   #   steps:
-  #     - uses: actions/checkout@v2
+  #     - uses: actions/checkout@v3
   #     - name: Setup Python
   #       uses: actions/setup-python@v4
   #       with: