How to implement caching using docker internal functionality?

[beeyev]

Here is an example, if I want to install some alpine packages with caching the sources to speed up the future build, I can do something like this:

RUN --mount=type=cache,target=/var/cache/apk/ apk add --quiet --update --no-cache \
    bash \
    tzdata

How can I cache mlocati/php-extension-installer source dependencies the same way? If it's possible, of course.

[dignac3]

I get problem optimizing the cache for this script too