Updated CI

Author: ankane

.github/workflows/build.yml

@@ -3,9 +3,15 @@ on: [push, pull_request]
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        dotnet: [9, 8]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: ${{ matrix.dotnet }}
       - uses: ankane/setup-postgres@v1
         with:
           database: pgvector_dotnet_test