Speedup workflow `selfbuild` and `test` using `sccache`

[NobodyXu]

• Use sccache to speedup workflow selfbuild and test.
• Add workflow cache-cleanup.yml to remove unused cache, since GHA does not allow main branch to use caches created by another branch.

TODO

• [ ] Set CARGO_BUILD_TARGET_DIR on workflow using sccache for better cache reuse. (cargo-install would automatically mkdir -p "${CARGO_BUILD_TARGET_DIR})
• [ ] Update cache-cleanup.yml from cargo-binstall
• [ ] Use sparse index: CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse If this is not good enough, then also cache index:

  - name: Configure index cache
    uses: actions/cache@v3
    with:
       path: |
        ~/.cargo/registry/index/
        ~/.cargo/registry/cache/
        ~/.cargo/git/db/
      key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}-${{ inputs.cache-suffix }}
      restore-keys: |
        ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}-
        ${{ runner.os }}-cargo-index-

• [ ] Replace sccache-action with taiki-e/install-action and then setup environments required manually:

  - name: Configure sccache
    uses: actions/github-script@v6
    with:
      script: |
        core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
        core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');

Signed-off-by: Jiahao XU Jiahao_XU@outlook.com

[NobodyXu]

The CI failed due to a bug in upstream https://github.com/rust-secure-code/cargo-auditable/issues/87

[NobodyXu]

Closed since according to my experience, sccache with GHA backend doesn't provide much speedup at all.