ci: make first build inplace

Author: henryiii

.github/workflows/ci.yml

@@ -123,24 +123,27 @@ jobs:
     - name: Configure C++11
       shell: bash
       run: >
-        cmake -S . -B build
+        cmake -S . -B .
         -DPYBIND11_WERROR=ON
         -DDOWNLOAD_CATCH=ON
         -DDOWNLOAD_EIGEN=ON
         -DCMAKE_CXX_STANDARD=11
         -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
 
     - name: Build C++11
-      run: cmake --build build -j 2
+      run: cmake --build . -j 2
 
     - name: Python tests C++11
-      run: cmake --build build --target pytest -j 2
+      run: cmake --build . --target pytest -j 2
 
     - name: C++11 tests
-      run: cmake --build build --target cpptest -j 2
+      run: cmake --build .  --target cpptest -j 2
 
     - name: Interface test C++11
-      run: cmake --build build --target test_cmake_build
+      run: cmake --build . --target test_cmake_build
+
+    - name: Clean directory
+      run: git clean -fdx
 
     - name: Configure C++${{ matrix.max-cxx-std }}
       shell: bash