add missing build flag

Author: joshuadavidthomas

.github/workflows/build.yml

@@ -40,7 +40,7 @@ jobs:
         uses: PyO3/maturin-action@v1
         with:
           target: ${{ matrix.platform.target }}
-          args: --release --out dist --find-interpreter
+          args: --release --out dist --find-interpreter --features extension-module
           sccache: "true"
           manylinux: auto
 
@@ -74,7 +74,7 @@ jobs:
         uses: PyO3/maturin-action@v1
         with:
           target: ${{ matrix.platform.target }}
-          args: --release --out dist --find-interpreter
+          args: --release --out dist --find-interpreter --features extension-module
           manylinux: musllinux_1_2
 
       - name: Upload wheels
@@ -104,7 +104,7 @@ jobs:
         uses: PyO3/maturin-action@v1
         with:
           target: ${{ matrix.platform.target }}
-          args: --release --out dist --find-interpreter
+          args: --release --out dist --find-interpreter --features extension-module
           sccache: "true"
 
       - name: Upload wheels
@@ -133,7 +133,7 @@ jobs:
         uses: PyO3/maturin-action@v1
         with:
           target: ${{ matrix.platform.target }}
-          args: --release --out dist --find-interpreter
+          args: --release --out dist --find-interpreter --features extension-module
           sccache: "true"
 
       - name: Upload wheels