Bump actions/checkout from 3 to 4 (#979)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

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/ci.yml

@@ -70,7 +70,7 @@ jobs:
     env:
       MIX_ENV: test
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: erlef/setup-beam@v1
         with:
           otp-version: ${{matrix.otp}}
@@ -129,7 +129,7 @@ jobs:
       - name: Set git to use original line ending
         run: |
           git config --global core.autocrlf false
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: erlef/setup-beam@v1
         with:
           otp-version: ${{matrix.otp}}
@@ -150,7 +150,7 @@ jobs:
           - elixir: 1.15.x
             otp: 25.x
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: erlef/setup-beam@v1
         with:
           otp-version: ${{matrix.otp}}

.github/workflows/docsite.yml

@@ -15,7 +15,7 @@ jobs:
       image: squidfunk/mkdocs-material
     steps: 
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Build
         run: mkdocs build -s
       - name: Upload artifact
@@ -32,7 +32,7 @@ jobs:
       max-parallel: 1
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Download artifact
         uses: actions/download-artifact@v3
         with:

.github/workflows/release-asset.yml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-20.04
     needs: release
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Validate version
         run: |