drop alpine 3.7 and 3.8 support

.gitlab-ci.yml

 .parallel:
   parallel:
     matrix:
-    - PHP_VERSION: "5"
-      ALPINE_VERSION: ["3.8", "3.7"]
-      TESTING_REPO: 0
-      PHP_SESSION: 0
 
     - PHP_VERSION: "7"
-      ALPINE_VERSION: ["3.15", "3.14", "3.13", "3.12", "3.11", "3.10", "3.9", "3.8", "3.7"]
+      ALPINE_VERSION: ["3.15", "3.14", "3.13", "3.12", "3.11", "3.10", "3.9"]
       TESTING_REPO: 0
       PHP_SESSION: 1