Fix python-tests dependency

Starting from b6113cc, it requires `build` package to be built.

.github/workflows/test.yml

@@ -51,7 +51,7 @@ jobs:
 
       - name: Install pip dependencies
         run: |
-          python -m pip install --upgrade pip setuptools wheel pytest bottle
+          python -m pip install --upgrade pip setuptools wheel pytest bottle build
           ./bin/build_pip.sh
           python -m pip install .