[Enh]: Use offical astral-sh/setup-uv@v2 github action and enable caching in the CI

[aidoskanapyanov]

We would like to learn about your use case. For example, if this feature is needed to adopt Narwhals in an open source project, could you please enter the link to it below?

No response

Please describe the purpose of the new feature or describe the problem to solve.

• We should use an official github action to install uv onto the running CI platform
• We can speed up the uv install CI step by caching the dependencies, since requirements-dev.txt does not change so often.

Suggest a solution if possible.

...
        with:
          python-version: ${{ matrix.python-version }}
-     - name: Install uv (Unix)
-       if: runner.os != 'Windows'
-       run: curl -LsSf https://astral.sh/uv/install.sh | sh
-     - name: Install uv (Windows)
-       if: runner.os == 'Windows'
-       run: powershell -c "irm https://astral.sh/uv/install.ps1 | iex"
+     - name: Install the latest version of uv
+       uses: astral-sh/setup-uv@v2
+       with:
+         version: "latest"
+     - name: Enable caching
+       id: setup-uv
+       uses: astral-sh/setup-uv@v2
+       with:
+         enable-cache: true
+         cache-suffix: "reqs-cache"
      - name: install-reqs
...

If you have tried alternatives, please describe them below.

No response

Additional information that may help us understand your needs.

No response

[MarcoGorelli]

sounds good, thanks - were you interested in making a pr with that suggested change?

[aidoskanapyanov]

Yeah, thanks, I'll draft a PR on these changes. I also need to read on cache-suffix, and see if I need a unique suffix for each workflow/run.