CI: restore actions/checkout@v3 for reliable checkout

.gitea/workflows/release.yml

@@ -39,15 +39,10 @@ jobs:
     name: Validate source
     runs-on: ubuntu-22.04
     steps:
-      - name: Checkout repository
-        run: |
-          # Build clone URL from server_url + repository
-          server_url="${{ gitea.server_url }}"
-          clone_url="${server_url}"
-          git clone "https://git:${RELEASE_TOKEN}@${clone_url#https://}/${{ gitea.repository }}" .
-          git checkout "${{ github.sha }}"
-          git log --oneline -3
-
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+          clean: true
       - name: Setup Python
         uses: actions/setup-python@v5
         with:
@@ -89,15 +84,10 @@ jobs:
         target: [linux, windows]
 
     steps:
-      - name: Checkout repository
-        run: |
-          # Build clone URL from server_url + repository
-          server_url="${{ gitea.server_url }}"
-          clone_url="${server_url}"
-          git clone "https://git:${RELEASE_TOKEN}@${clone_url#https://}/${{ gitea.repository }}" .
-          git checkout "${{ github.sha }}"
-
-      - name: Setup Python
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+          clean: true
         uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}