Ignore php dependency only

Author: kocsismate

.github/workflows/continuous-integration.yml

@@ -115,11 +115,11 @@ jobs:
 
       - name: "Install lowest dependencies with composer"
         if: matrix.dependencies == 'lowest'
-        run: composer update --no-interaction --no-progress --no-plugins --prefer-lowest --ignore-platform-reqs
+        run: composer update --no-interaction --no-progress --no-plugins --prefer-lowest --ignore-platform-reqs=php
 
       - name: "Install highest dependencies with composer"
         if: matrix.dependencies == 'highest'
-        run: composer update --no-interaction --no-progress --no-plugins --ignore-platform-reqs
+        run: composer update --no-interaction --no-progress --no-plugins --ignore-platform-reqs=php
 
       - name: "Run unit tests"
         run: vendor/bin/phpunit --verbose