Fix just-tests workflow to not require full dev deps

Author: thatch

.github/workflows/build.yml

@@ -29,12 +29,9 @@ jobs:
       - name: Install
         run: |
           python -m pip install --upgrade pip
-          make setup
           pip install -U .
       - name: Test
-        run: make test
-      - name: Lint
-        run: make lint
+        run: python -m metadata_please.tests
 
   metadata_please:
     runs-on: ${{ matrix.os }}