chore: fix Dockerfile FROM quotes, gitlabci image quotes, add python image lookup fix

.gitlab-ci.yml

@@ -1,4 +1,4 @@
-image: "docker:latest"
+image: docker:latest
 
 services:
   - "docker:dind"

Dockerfile

@@ -1,4 +1,4 @@
-FROM "python:3.7-alpine"
+FROM python:3.7-alpine
 
 ARG BUILD_DATE
 ARG VCS_REF

renovate.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "gitlabci": {
+    "enabled": true
+  },
+  "packageRules": [
+    {
+      "description": "python Docker image was deprecated; use replacementLookup",
+      "matchDatasources": ["docker"],
+      "matchPackageNames": ["python"],
+      "replacementName": "python",
+      "replacementVersion": "3.13-alpine"
+    }
+  ]
+}