Use sccache or actions/cache@v2 improve build time

[aslamplr]

Use sccache improve build time.

Refer xiph/rav1e@49c0e45

Consider using actions/cache@v2:

https://github.com/denoland/deno/blob/0ffc99a61ddfa958a436beef0d003ecead630d0f/.github/workflows/ci.yml#L98

https://github.com/denoland/deno/blob/0ffc99a61ddfa958a436beef0d003ecead630d0f/.github/workflows/ci.yml#L106

[aslamplr]

Setup sccache locally, it's working. It is useful only in case there is a clean build. My workflow doesn't have a clean build as of now. So no improvement locally. But its too early to say so.

On CI, it would be good to go with actions/cache@v2 since it's more native to GitHub Actions and the storage is native as well. If we go with sccache we need to provide storage externally either via s3 or azure that wouldn't be a good choice as we are going minimalistic ATM.