Fix SYMFONY_REQUIRE env var.

Author: kbond

.github/workflows/ci-linux.yaml

@@ -32,7 +32,7 @@ jobs:
                     - 1337:1337
 
         env:
-            SYMFONY_VERSION: ${{ matrix.symfony-version }}
+            SYMFONY_REQUIRE: ${{ matrix.symfony-version }}
 
         strategy:
             fail-fast: false