feat: use node v20.12.1 and use node-slim instead of alpine (#205)

Fixes #204

.github/workflows/validate.yml

@@ -13,7 +13,7 @@ jobs:
 
       - uses: actions/setup-node@v3
         with:
-          node-version: 20.11.0
+          node-version-file: '.nvmrc'
 
       - run: npm ci
 

.nvmrc

@@ -1 +1 @@
-v20.11.0
+v20.12.1

Dockerfile

@@ -1,6 +1,8 @@
-FROM node:20.11.0-alpine
+FROM node:20.12.1-slim
 
-RUN apk add --no-cache git
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends ca-certificates git \
+    && rm -rf /var/lib/apt/lists/*
 
 # nice clean home for our action files
 RUN mkdir /action