Update Dockerfile

Dockerfile

@@ -1,4 +1,4 @@
-FROM kuzzleio/kuzzle-runner:16 as builder
+FROM kuzzleio/kuzzle-runner:18 AS builder
 
 ADD . /var/app
 
@@ -7,7 +7,7 @@ WORKDIR /var/app
 RUN npm ci
 RUN npm run build
 
-FROM kuzzleio/kuzzle-runner:16 as prepare
+FROM kuzzleio/kuzzle-runner:18 AS prepare
 
 WORKDIR /var/app
 ENV NODE_ENV=production
@@ -16,7 +16,7 @@ COPY --from=builder /var/app/package*.json /var/app/.npmrc* /var/app/dist ./
 RUN npm install --production
 
 # Final image
-FROM node:16-stretch-slim as production
+FROM node:18-stretch-slim AS production
 
 ARG KUZZLE_VAULT_KEY
 ENV KUZZLE_VAULT_KEY=$KUZZLE_VAULT_KEY