ci: Drop Python 3.9 from testing matrix

In preparation of removing support for Python 3.9 remove it from the
test matrix.

Signed-off-by: Pieter De Gendt <[email protected]>

Author: pdgendt

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13']
     steps:
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2