github: Drop CMake install

The base image already has cmake so drop it.

Author: penberg

.github/workflows/CI.yml

@@ -68,10 +68,6 @@ jobs:
         target: [aarch64]
     steps:
       - uses: actions/checkout@v3
-      - name: Setup cmake
-        uses: jwlawson/actions-setup-cmake@v1.14
-        with:
-          cmake-version: '3.18.x'
       - uses: actions/setup-python@v4
         env:
           CXX: clang++