Fix actions/cache ::set-output deprecated

GitHub Actions log messages: "The `set-output` command is deprecated and
    will be disabled soon. Please upgrade to using Environment Files.

    * More info:

https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

    * And on the official actions/cache@3 documentation page where an
example
    is given:
https://github.com/actions/cache/blob/main/examples.md\#php---comp
oser

Author: pH-7

.github/workflows/ci-test.yml

@@ -32,7 +32,7 @@ jobs:
 
       - name: Get Composer Cache Directory
         id: composer-cache
-        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+        run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
 
       - name: Cache Composer dependencies
         uses: actions/cache@v3