onnxsim: fix matrix so both cp311 and cp312 actually build

An include list whose entries share no key with the base matrix
collapses onto a single job instead of adding one per entry (confirmed
against onnxoptimizer's own CI run, which built only cp312 despite
listing cp311 too). Make python a real matrix dimension so include only
attaches onnxruntime to the matching combination.

Author: luhenry

.github/workflows/build-onnxsim.yml

@@ -48,14 +48,17 @@ jobs:
       fail-fast: false
       matrix:
         version: ${{ fromJSON(needs.setup.outputs.versions) }}
-        # Upstream ships cp310/cp311/cp312-abi3 (no free-threaded wheel here: our
-        # matrix mirrors onnxoptimizer's, which onnxsim vendors and links the
-        # same way). cp310 is dropped: onnx (the runtime dependency) has no
-        # riscv64 wheel for it on our registry, at any version, and no
-        # py3-none-any fallback either (it's a compiled extension). cp311 stays:
-        # onnx ships a riscv64 cp311 wheel, and nanobind/protobuf (the other
-        # build-time dependencies) resolve too, via their py3-none-any fallback
-        # wheels.
+        # Upstream ships cp310/cp311/cp312-abi3 (no free-threaded wheel here).
+        # cp310 is dropped: onnx (the runtime dependency) has no riscv64 wheel
+        # for it on our registry, at any version, and no py3-none-any fallback
+        # either (it's a compiled extension). cp311 stays: onnx ships a
+        # riscv64 cp311 wheel, and nanobind/protobuf (the other build-time
+        # dependencies) resolve too, via their py3-none-any fallback wheels.
+        # `python` is a real matrix dimension (not folded into `include`
+        # alone) so both entries actually produce a job: an `include` list
+        # whose entries share no key with the base matrix collapses onto a
+        # single combination instead of adding one job per entry.
+        python: [cp311, cp312]
         include:
           - python: cp311
             # No riscv64 onnxruntime wheel on cp311; the rest of the suite still