Github Actions: add a job which tests the lowest supported versions (#4220)

* Github Actions: add a job which tests the lowest supported versions

* Update tests.yaml

* run lowest only on php 7.2

to reduce the number of generated jobs

* faise min webmozart/assert version

we need at least https://github.com/webmozart/assert/pull/160

* use quotes

.github/workflows/tests.yaml

@@ -12,6 +12,10 @@ jobs:
         strategy:
             matrix:
                 php: ['7.2', '7.3', '7.4']
+                dependencies: ['locked']
+                include:
+                    - php: '7.2'
+                      dependencies: 'lowest'
 
         name: PHP ${{ matrix.php }} tests
         steps:
@@ -25,5 +29,8 @@ jobs:
             -   name: Setup Problem Matchers for PHPUnit
                 run: echo "::add-matcher::${{ runner.tool_cache }}/phpunit.json"
 
+            -   run: composer update --prefer-lowest --no-progress --ansi
+                if: "matrix.dependencies == 'lowest'"
             -   run: composer install --no-progress --ansi
+                if: "matrix.dependencies != 'lowest'"
             -   run: vendor/bin/phpunit

composer.json

@@ -39,7 +39,7 @@
         "symplify/set-config-resolver": "^8.2.20",
         "symplify/smart-file-system": "^8.2.20",
         "tracy/tracy": "^2.7",
-        "webmozart/assert": "^1.0"
+        "webmozart/assert": "^1.8"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.16",