Revert "ci: update node version to v20"

This reverts commit 0e64d60.

Author: escapedcat

Diff for: .github/workflows/CI.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04, windows-2022]
-        node: [20]
+        node: [18, 20]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4

Diff for: Dockerfile.ci

@@ -1,4 +1,4 @@
-FROM docker.io/library/node:20-buster AS builder
+FROM docker.io/library/node:18-buster AS builder
 WORKDIR /src
 COPY . ./
 RUN yarn install && \
@@ -23,7 +23,7 @@ RUN yarn install && \
     # Default commitlint config
     npm pack @commitlint/config-conventional
 
-FROM docker.io/library/node:20-buster
+FROM docker.io/library/node:18-buster
 COPY --from=builder /src/*.tgz ./
 RUN npm install -g *.tgz && \
     rm -rf *.tgz