Migrate get-distribution-variants to docker-actions [DI-580] (#29)

See hazelcast/hazelcast-docker#1165

Changes:
- workflow migrated to composite action to match repo style
- output inlined

_Partially addresses_:
[DI-580](https://hazelcast.atlassian.net/browse/DI-580)

[DI-580]:
https://hazelcast.atlassian.net/browse/DI-580?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

---------

Co-authored-by: Łukasz Dziedziul <[email protected]>

Author: JackPGreen

.github/workflows/test-get-distribution-classifiers.yml

@@ -0,0 +1,28 @@
+name: Test get-distribution-classifiers action
+
+on:
+  workflow_call:
+
+jobs:
+  get:
+    outputs:
+      distribution-classifiers: ${{ steps.distribution-classifiers.outputs.classifiers }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - id: distribution-classifiers
+        uses: ./get-distribution-classifiers
+
+  # Doesn't explicitly assert, but validates that the output is valid for matrix consumption
+  test:
+    runs-on: ubuntu-latest
+    needs:
+      - get
+    strategy:
+      matrix:
+        classifier: ${{ fromJSON(needs.get.outputs.distribution-classifiers) }}
+    steps:
+      - run: echo "classifier=${{ matrix.classifier }}"
+

.github/workflows/test.yml

@@ -22,6 +22,9 @@ jobs:
   test-download-hz-dist:
     uses: ./.github/workflows/test-download-hz-dist.yml
 
+  test-get-distribution-classifiers:
+    uses: ./.github/workflows/test-get-distribution-classifiers.yml
+
   test-get-hz-versions:
     uses: ./.github/workflows/test-get-hz-versions.yml
 
@@ -45,6 +48,7 @@ jobs:
       - test-check-if-latest-lts-release
       - test-check-redhat-service-status
       - test-download-hz-dist
+      - test-get-distribution-classifiers
       - test-get-hz-versions
       - test-get-supported-jdks
       - test-get-supported-platforms

get-distribution-classifiers/action.yml

@@ -0,0 +1,11 @@
+name: Get distribution classifiers
+
+outputs:
+  classifiers:
+    value: '["slim", ""]'
+
+runs:
+  using: "composite"
+  steps:
+    - shell: bash
+      run: exit 0