ci: stop requesting the runner's preinstalled cabal - #9

Process completed with exit code 1.

Expected an assignment or function call and instead saw an expression

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v4, actions/setup-node@v4, actions/setup-python@v5, astral-sh/setup-uv@v4, pnpm/action-setup@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/