[K8s] Fix default runtime build broken by Debian Buster EOL (#1460)

Co-authored-by: Maciej Skuratowski <mskuratowski@Maciejs-MacBook-Air.local>

Author: mskuratowski

lithops/serverless/backends/k8s/k8s.py

@@ -169,10 +169,10 @@ def _build_default_runtime(self, docker_image_name):
         """
         Builds the default runtime
         """
-        # Build default runtime using local dokcer
-        dockerfile = "Dockefile.default-k8s-runtime"
+        # Build default runtime using local docker
+        dockerfile = "Dockerfile.default-k8s-runtime"
         with open(dockerfile, 'w') as f:
-            f.write(f"FROM python:{utils.CURRENT_PY_VERSION}-slim-buster\n")
+            f.write(f"FROM python:{utils.CURRENT_PY_VERSION}-slim-bookworm\n")
             f.write(config.DOCKERFILE_DEFAULT)
         try:
             self.build_runtime(docker_image_name, dockerfile)

runtime/kubernetes/Dockerfile

@@ -1,17 +1,17 @@
-# Python 3.6
-#FROM python:3.6-slim-buster
-
-# Python 3.7
-#FROM python:3.7-slim-buster
-
 # Python 3.8
-#FROM python:3.8-slim-buster
+#FROM python:3.8-slim-bookworm
 
 # Python 3.9
-#FROM python:3.9-slim-buster
+#FROM python:3.9-slim-bookworm
 
 # Python 3.10
-FROM python:3.10-slim-buster
+FROM python:3.10-slim-bookworm
+
+# Python 3.11
+#FROM python:3.11-slim-bookworm
+
+# Python 3.12
+#FROM python:3.12-slim-bookworm
 
 RUN apt-get update && apt-get install -y \
         zip redis-server curl \