ci: use pixi github action

Author: tony-p

.github/workflows/pixi.yaml

@@ -13,27 +13,21 @@ jobs:
       matrix:
         include:
         - os: windows-latest
-          shell: "pwsh -Login {0}"
-          pixi_install: "iwr -useb https://pixi.sh/install.ps1 | iex"
           build_depend: vs2022_win-64=19.*
           tests_command: "'PATH=\\\"$PATH;build/Release\\\" build/tests/Release/behaviortree_cpp_test.exe'"
         - os: ubuntu-latest
-          shell: "bash -el {0}"
-          pixi_install: "curl -fsSL https://pixi.sh/install.sh | bash"
           build_depend: "gxx=12.2.*"
           tests_command: "./build/tests/behaviortree_cpp_test"
     runs-on: ${{ matrix.os }}
-    defaults:
-      run:
-        shell: ${{ matrix.shell }}
     steps:
       # Pixi is the tool used to create/manage conda environment
-      - name: Set up pixi
-        run: |
-          ${{ matrix.pixi_install }}
-      - name: Setup windows path
-        if: "startsWith(runner.os, 'windows')"
-        run: echo "C:\Users\runneradmin\AppData\Local\pixi\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+      - uses: prefix-dev/setup-pixi@v0.4.1
+        with:
+          pixi-version: v0.7.0
+          locked: false
+          frozen: false
+          run-install: false
+          manifest-path: build-env/pixi.yaml
       - name: Make pixi workspace
         run: |
           pixi init build-env