Update Elixir for Gitlab CI

.gitlab-ci.yml

@@ -5,6 +5,12 @@
 # Container Scanning customization: https://docs.gitlab.com/ee/user/application_security/container_scanning/#customizing-the-container-scanning-settings
 # Note that environment variables can be set in several places
 # See https://docs.gitlab.com/ee/ci/variables/#cicd-variable-precedence
+
+variables:
+  ELIXIR_VERSION: 1.15.2
+  OTP_VERSION: 26.0.2
+  ALPINE_VERSION: 3.18.2
+
 stages:
 - test
 sast:
@@ -13,7 +19,7 @@ include:
 - template: Security/SAST.gitlab-ci.yml
 
 .elixir: &elixir
-  image: elixir:1.13
+  image: 'hexpm/elixir:$ELIXIR_VERSION-erlang-$OTP_VERSION-alpine-$ALPINE_VERSION'
   before_script:
     - mix local.hex --force
     - mix local.rebar --force