chore(deps): bump shivammathur/setup-php from 2.26.0 to 2.28.0

Bumps [shivammathur/setup-php](https://github.com/shivammathur/setup-php) from 2.26.0 to 2.28.0.
- [Release notes](https://github.com/shivammathur/setup-php/releases)
- [Commits](shivammathur/setup-php@2.26.0...2.28.0)

---
updated-dependencies:
- dependency-name: shivammathur/setup-php
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/continuous-integration.yml

@@ -59,7 +59,7 @@ jobs:
           sudo apt-get install -y libcriterion3 libcriterion-dev
 
       - name: "Install PHP"
-        uses: "shivammathur/setup-php@2.26.0"
+        uses: "shivammathur/setup-php@2.28.0"
         with:
           php-version: "${{ matrix.php }}"
           extensions: "intl-${{ matrix.icu }}"
@@ -104,7 +104,7 @@ jobs:
           valgrind --version
 
       - name: "Install PHP"
-        uses: "shivammathur/setup-php@2.26.0"
+        uses: "shivammathur/setup-php@2.28.0"
         with:
           php-version: "latest"
           extensions: "intl-73.2"
@@ -157,7 +157,7 @@ jobs:
           sudo apt-get install -y libcriterion3 libcriterion-dev
 
       - name: "Install PHP"
-        uses: "shivammathur/setup-php@2.26.0"
+        uses: "shivammathur/setup-php@2.28.0"
         with:
           php-version: "${{ matrix.php }}"
           extensions: "intl-${{ matrix.icu }}"