Bump the dependencies group across 1 directory with 2 updates (#156)

Bumps the dependencies group with 2 updates in the / directory: [actions/checkout](https://github.com/actions/checkout) and [prefix-dev/setup-pixi](https://github.com/prefix-dev/setup-pixi).

Updates `actions/checkout` from 5 to 6
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

Updates `prefix-dev/setup-pixi` from 0.9.1 to 0.9.3
- [Release notes](https://github.com/prefix-dev/setup-pixi/releases)
- [Commits](prefix-dev/setup-pixi@v0.9.1...v0.9.3)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dependencies
- dependency-name: prefix-dev/setup-pixi
  dependency-version: 0.9.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

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/test.yml

@@ -25,10 +25,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source files
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Pixi
-        uses: prefix-dev/setup-pixi@v0.9.1
+        uses: prefix-dev/setup-pixi@v0.9.3
 
       - name: Run unit tests
         run: pixi run test
@@ -37,10 +37,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source files
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Pixi
-        uses: prefix-dev/setup-pixi@v0.9.1
+        uses: prefix-dev/setup-pixi@v0.9.3
 
       - name: Run static type analysis
         run: pixi run mypy
@@ -49,10 +49,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source files
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Pixi
-        uses: prefix-dev/setup-pixi@v0.9.1
+        uses: prefix-dev/setup-pixi@v0.9.3
 
       - name: Validate "prod" installation
         run: bin/build.sh