build(deps): bump prefix-dev/setup-pixi from 0.9.3 to 0.9.4

Bumps [prefix-dev/setup-pixi](https://github.com/prefix-dev/setup-pixi) from 0.9.3 to 0.9.4.
- [Release notes](https://github.com/prefix-dev/setup-pixi/releases)
- [Commits](prefix-dev/setup-pixi@v0.9.3...v0.9.4)

---
updated-dependencies:
- dependency-name: prefix-dev/setup-pixi
  dependency-version: 0.9.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

.github/workflows/ex-rtd.yml

@@ -115,7 +115,7 @@ jobs:
           pandoc --version
 
       - name: Setup pixi
-        uses: prefix-dev/setup-pixi@v0.9.3
+        uses: prefix-dev/setup-pixi@v0.9.4
         with:
           pixi-version: v0.41.4
           manifest-path: modflow6-examples/pixi.toml

.github/workflows/ex-workflow.yml

@@ -30,7 +30,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Setup pixi
-        uses: prefix-dev/setup-pixi@v0.9.3
+        uses: prefix-dev/setup-pixi@v0.9.4
         with:
           pixi-version: v0.41.4
 
@@ -60,7 +60,7 @@ jobs:
           path: modflow6
 
       - name: Setup pixi
-        uses: prefix-dev/setup-pixi@v0.9.3
+        uses: prefix-dev/setup-pixi@v0.9.4
         with:
           pixi-version: v0.41.4
           manifest-path: modflow6-examples/pixi.toml
@@ -133,7 +133,7 @@ jobs:
           path: usgslatex
 
       - name: Setup pixi
-        uses: prefix-dev/setup-pixi@v0.9.3
+        uses: prefix-dev/setup-pixi@v0.9.4
         with:
           pixi-version: v0.41.4
           manifest-path: modflow6-examples/pixi.toml