ci(test): add eslint and prettier

.gitlab-ci.yml

-image: node:18.15.0
+image: node:18
+
 
 stages:
   - test
 
+
 # === Caches ===
 .yarn-cache: &yarn-cache
   key: yarn-$CI_JOB_IMAGE
   paths:
     - .yarn
 
+
 # === Proxy ===
 # Description: sets up the proxy needed for the runner inside of the PTB. Produces a build.env that is used in the next jobs
 proxy:
@@ -39,9 +42,10 @@ proxy:
   # install deps
   - yarn install --immutable
 
+
 # === Job: Unit Tests ===
 # Description: this job runs the unit tests
-test:
+unit_tests:
   stage: test
   needs: ["proxy"]
   script:
@@ -54,3 +58,16 @@ test:
     reports:
       junit:
         - junit.xml
+
+
+# === Job: ESLint and Prettier ===
+# Description: this job runs ESLint and Prettier
+lint:
+  stage: test
+  needs: ["proxy"]
+  script:
+    - *yarn-install
+    - yarn run test:lint
+    - yarn run test:prettier
+  cache:
+    - <<: *yarn-cache