chore(deps): update elixir docker tag to v1.15.6 (#46)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| elixir | docker | patch | `1.15.4-slim` -> `1.15.6-slim` |
| elixir |  | patch | `1.15.4-slim` -> `1.15.6-slim` |

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
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Reviewed-on: #46
Co-authored-by: renovate-bot <renovate-bot@dubas.dev>
Co-committed-by: renovate-bot <renovate-bot@dubas.dev>

.drone.yml

@@ -37,7 +37,7 @@ steps:
       restore: true
 
   - name: test
-    image: 'elixir:1.15.4-slim'
+    image: 'elixir:1.15.6-slim'
     environment:
       MIX_ENV: test
       POSTGRES_HOST: db
@@ -49,7 +49,7 @@ steps:
       - mix test --cover --trace --slowest 10
 
   - name: lint
-    image: 'elixir:1.15.4-slim'
+    image: 'elixir:1.15.6-slim'
     commands:
       - mix do local.rebar --force, local.hex --force, deps.get, deps.compile
       - mix compile

docker-compose.yml

@@ -13,7 +13,7 @@ services:
       - 'db_data:/var/lib/postgresql/data'
     restart: unless-stopped
   app:
-    image: 'elixir:1.15.4-slim'
+    image: 'elixir:1.15.6-slim'
     hostname: app
     depends_on:
       - db