Use python v3.13 for build tests

Author: h2zero

.github/workflows/build.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - name: Install platformio
         run: |
           python -m pip install --upgrade pip
@@ -100,7 +100,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - name: Install platformio
         run: |
           python -m pip install --upgrade pip
@@ -146,7 +146,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - name: Install platformio
         run: |
           python -m pip install --upgrade pip
@@ -301,7 +301,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - name: Install platformio
         run: |
           python -m pip install --upgrade pip
@@ -344,7 +344,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.13"
       - name: Install platformio
         run: |
           python -m pip install --upgrade pip