fix(build): correct Python command invocations for build

Updated the build script to use `python3` and `pip3` commands, ensuring compatibility with environments where Python 2 might be the default. Also added `--break-system-packages` flag to `pip3` install to handle specific package installations without breaking the environment.

.forgejo/workflows/build.yml

@@ -17,11 +17,11 @@ jobs:
         run: |
           apt update
           apt install -y python3 python3-pip
-          python -m pip install --upgrade pip
-          pip install -r requirements.txt
+          python3 -m pip install --upgrade pip
+          pip3 install -r requirements.txt --break-system-packages
 
       - name: Generate static site
-        run: python main.py
+        run: python3 main.py
 
       - name: Deploy to pages branch
         run: |