update unit tests ci

Author: federico-stacks

.github/workflows/stacks-core-tests.yml

@@ -31,7 +31,7 @@ jobs:
       matrix:
         ## Partition the tests into 8 jobs
         ##   - This is used in a later step when running `cargo nextest run ... --partition count:num/8`
-        partition: [1, 2, 3, 4, 5, 6, 7, 8]
+        partition: [1, 2, 3, 4, 5, 6, 7, 8, 9]
     steps:
       ## Setup test environment
       - name: Setup Test Environment
@@ -48,7 +48,7 @@ jobs:
         uses: stacks-network/actions/stacks-core/run-tests/partition@main
         with:
           partition: ${{ matrix.partition }}
-          total-partitions: 8
+          total-partitions: 9
 
       ## Create and upload code coverage file
       - name: Code Coverage