Support dynamic values for PUB-CACHE-PATH

[beninato8]

In the caching section of the README, both CACHE-PATH and PUB-CACHE-PATH are supposed to support dynamic values, like :version: and :arch:.

I wanted to implement caching for my usage of subosito/flutter-action@v2, so I tried adding the block from the README:

- name: Set up Flutter
    uses: subosito/flutter-action@v2
    id: flutter-action
    with:
        flutter-version: "3.27.x"
        channel: "stable"
        cache: true
        cache-key: "flutter-:os:-:channel:-:version:-:arch:-:hash:"
        cache-path: "${{ runner.tool_cache }}/flutter/:channel:-:version:-:arch:"
        pub-cache-key: "flutter-pub:os:-:channel:-:version:-:arch:-:hash:"
        pub-cache-path: "${{ runner.tool_cache }}/flutter/:channel:-:version:-:arch:"

In my action output, I saw that PUB_CACHE_PATH still contained the placeholders:

Run subosito/flutter-action@v2
with:
  flutter-version: 3.27.x
  channel: stable
  cache: true
  cache-key: flutter-:os:-:channel:-:version:-:arch:-:hash:
  cache-path: /opt/hostedtoolcache/flutter/:channel:-:version:-:arch:
  pub-cache-key: flutter-pub:os:-:channel:-:version:-:arch:-:hash:
  pub-cache-path: /opt/hostedtoolcache/flutter/:channel:-:version:-:arch:
  architecture: X64
  dry-run: false
  git-source: https://github.com/flutter/flutter.git

$GITHUB_ACTION_PATH/setup.sh -p \
  -n '3.27.x' \
  -f '' \
  -a 'X64' \
  -k 'flutter-:os:-:channel:-:version:-:arch:-:hash:' \
  -c '/opt/hostedtoolcache/flutter/:channel:-:version:-:arch:' \
  -l 'flutter-pub:os:-:channel:-:version:-:arch:-:hash:' \
  -d '/opt/hostedtoolcache/flutter/:channel:-:version:-:arch:' \
  -g 'https://github.com/flutter/flutter.git' \
  stable

Run actions/cache@v4
with:
  path: /opt/hostedtoolcache/flutter/stable-3.27.4-x64
  key: flutter-linux-stable-3.27.4-x64-d8a9f9a52e5af486f80d932e838ee93861ffd863
  enableCrossOsArchive: false
  fail-on-cache-miss: false
  lookup-only: false
  save-always: false

Run actions/cache@v4
with:
  path: /opt/hostedtoolcache/flutter/:channel:-:version:-:arch:
  key: flutter-publinux-stable-3.27.4-x64-d8a9f9a52e5af486f80d932e838ee93861ffd863-a0844170cef72d2be5a80509b7e7b13d0f906f8012f6585ea075b5ec0b48ed3f
  enableCrossOsArchive: false
  fail-on-cache-miss: false
  lookup-only: false
  save-always: false

$GITHUB_ACTION_PATH/setup.sh \
  -n '3.27.4' \
  -a 'x64' \
  -c '/opt/hostedtoolcache/flutter/stable-3.27.4-x64' \
  -d '/opt/hostedtoolcache/flutter/:channel:-:version:-:arch:' \
  stable

This PR applies the expand_key function on PUB_CACHE, updates the README to fix a missing dash in the example path (to match the default [ -z "$PUB_CACHE_KEY" ] && PUB_CACHE_KEY="flutter-pub-:os:-:channel:-:version:-:arch:-:hash:"), and adds tests for PUB_CACHE_KEY and PUB_CACHE_PATH.

Before this change:

./setup.sh -p -t -d '/opt/hostedtoolcache/flutter/:channel:-:version:-:arch:'
CHANNEL=stable
VERSION=3.7.7
ARCHITECTURE=x64
CACHE-KEY=flutter-linux-stable-3.7.7-x64-2ad6cd72c040113b47ee9055e722606a490ef0da
CACHE-PATH=/opt/hostedtoolcache/flutter/stable-3.7.7-x64
PUB-CACHE-KEY=flutter-pub-linux-stable-3.7.7-x64-2ad6cd72c040113b47ee9055e722606a490ef0da
PUB-CACHE-PATH=/opt/hostedtoolcache/flutter/:channel:-:version:-:arch:

After this change:

./setup.sh -p -t -d '/opt/hostedtoolcache/flutter/:channel:-:version:-:arch:'
CHANNEL=stable
VERSION=3.7.7
ARCHITECTURE=x64
CACHE-KEY=flutter-linux-stable-3.7.7-x64-2ad6cd72c040113b47ee9055e722606a490ef0da
CACHE-PATH=/opt/hostedtoolcache/flutter/stable-3.7.7-x64
PUB-CACHE-KEY=flutter-pub-linux-stable-3.7.7-x64-2ad6cd72c040113b47ee9055e722606a490ef0da
PUB-CACHE-PATH=/opt/hostedtoolcache/flutter/stable-3.7.7-x64

[bartekpacia]

Thx!