ci: drop some conda runs

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

Author: henryiii

.github/workflows/conda.yml

@@ -12,8 +12,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        platform: [ubuntu-latest, macos-12, windows-2019]
-        python-version: ["3.9", "3.11"]
+        platform: [ubuntu-latest]
+        python-version: ["3.10", "3.13"]
 
     runs-on: ${{ matrix.platform }}