ci: use mise-action for environment setup

Author: alexey1312

.github/workflows/ci.yml

@@ -18,9 +18,9 @@ jobs:
         with:
           lfs: true
 
-      - name: Setup mise environment
-        run: source Scripts/environment.sh
-        shell: bash
+      - uses: jdx/mise-action@v3
+        with:
+          experimental: true
 
       - name: Check formatting (Swift + Markdown)
         run: bin/mise run format-check
@@ -48,9 +48,9 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-spm-
 
-      - name: Setup mise environment
-        run: source Scripts/environment.sh
-        shell: bash
+      - uses: jdx/mise-action@v3
+        with:
+          experimental: true
 
       - name: Show Swift version
         run: swift --version