use alpine image instead debian

.drone.yml

@@ -41,5 +41,4 @@ steps:
       - docker logout "$REGISTRY"
     when:
       event: tag
-
 ...

README.md

@@ -5,3 +5,4 @@ Baseimage for CI tasks
 ---
 
 - [yamllint git](https://github.com/adrienverge/yamllint)
+- [alpine](https://pkgs.alpinelinux.org/packages?name=yamllint)

image/Dockerfile

@@ -1,8 +1,8 @@
-FROM debian:bullseye-slim
+FROM alpine:3.14
 
-RUN apt-get update && \
-    apt-get install -y yamllint && \
-    rm -rf /var/lib/apt/lists/*
+RUN \
+  apk update && apk upgrade && \
+  apk add --no-cache yamllint==1.26.1-r0
 
 COPY relaxed.yaml /yamllint/relaxed.yaml