[TASK] Simplify the configuration for the static analysis CI job (MyIntervals#439)

Author: oliverklee

.github/workflows/ci.yml

@@ -93,13 +93,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        include:
-          - command: sniffer
-            php-version: '7.4'
-          - command: fixer
-            php-version: '7.4'
-          - command: stan
-            php-version: '7.4'
+        command:
+          - sniffer
+          - fixer
+          - stan
+        php-version:
+          - '7.4'
 
     steps:
       - name: Checkout