fix(ci): install Node.js 20 needed by newer GitHub Actions runner

The actions/download-artifact action is failing with the following
message:

    /__e/node20/bin/node: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.27' not found (required by /__e/node20/bin/node)

The problem is that GitHub Actions is dropping Node.js 16 support [1],
and their Node.js 20 binary is too new for our Ubuntu 18.04 Docker
images.

Install our own copy of Node.js 20 which is compatible with Ubuntu
18.04.

[1] https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

.github/workflows/build-static.yml

@@ -152,7 +152,7 @@ jobs:
           - {runs_on: ubuntu-latest, docker_container: "debian:buster", name: "Debian 10 Buster", archive_name: "linux", exe_file: "bin/quick-lint-js"}
           - {runs_on: ubuntu-latest, docker_container: "fedora:35", name: "Fedora 35", archive_name: "linux", exe_file: "bin/quick-lint-js"}
           - {runs_on: ubuntu-latest, docker_container: "fedora:36", name: "Fedora 36", archive_name: "linux", exe_file: "bin/quick-lint-js"}
-          - {runs_on: ubuntu-latest, docker_container: "ubuntu:18.04", name: "Ubuntu 18.04 LTS Bionic", archive_name: "linux", exe_file: "bin/quick-lint-js"}
+          - {runs_on: ubuntu-latest, docker_container: "ubuntu:18.04", name: "Ubuntu 18.04 LTS Bionic", archive_name: "linux", exe_file: "bin/quick-lint-js", install_node_20_ubuntu: true}
           - {runs_on: ubuntu-latest, docker_container: "ubuntu:20.04", name: "Ubuntu 20.04 LTS Focal", archive_name: "linux", exe_file: "bin/quick-lint-js"}
     runs-on: ${{ matrix.os.runs_on }}
     container: ${{ matrix.os.docker_container }}
@@ -171,6 +171,16 @@ jobs:
           uname -a || :
         shell: bash
 
+      # Node.js 20 is required by actions/download-artifact.
+      # TODO(strager): Bake this step into the Docker image.
+      - name: install Node.js 20 on Ubuntu
+        if: ${{ matrix.os.install_node_20_ubuntu }}
+        run: |
+          curl -sL https://deb.nodesource.com/setup_18.x -o nodesource_setup.sh
+          bash nodesource_setup.sh
+          apt-get install nodejs
+        shell: bash
+
       - uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a # v3.0.2
         with:
           name: quick-lint-js-${{ matrix.os.archive_name }}-${{ github.sha }}

.github/workflows/debian-package.yml

@@ -68,8 +68,8 @@ jobs:
           - {arch: amd64, runs_on: ubuntu-latest, docker_container: "debian:buster", name: "Debian 10 Buster"}
           - {arch: amd64, runs_on: ubuntu-latest, docker_container: "pureos/pureos:amber-latest", name: "PureOS Amber"}
           - {arch: amd64, runs_on: ubuntu-latest, docker_container: "ubuntu:16.04", name: "Ubuntu 16.04 LTS Xenial"}
-          - {arch: amd64, runs_on: ubuntu-latest, docker_container: "ubuntu:18.04", name: "Ubuntu 18.04 LTS Bionic"}
-          - {arch: amd64, runs_on: ubuntu-latest, docker_container: "ubuntu:20.04", name: "Ubuntu 20.04 LTS Focal"}
+          - {arch: amd64, runs_on: ubuntu-latest, docker_container: "ubuntu:18.04", name: "Ubuntu 18.04 LTS Bionic", install_node_20_ubuntu: true}
+          - {arch: amd64, runs_on: ubuntu-latest, docker_container: "ubuntu:20.04", name: "Ubuntu 20.04 LTS Focal", install_node_20_ubuntu: true}
           - {arch: arm64, runs_on: stracle-linux-aarch64, docker_container: "debian:bullseye", name: "Debian 11 Bullseye"}
           - {arch: arm64, runs_on: stracle-linux-aarch64, docker_container: "debian:buster", name: "Debian 10 Buster"}
           - {arch: arm64, runs_on: stracle-linux-aarch64, docker_container: "ubuntu:20.04", name: "Ubuntu 20.04 LTS Focal"}
@@ -89,8 +89,19 @@ jobs:
           uname -a || :
 
       - name: update apt
+        if: ${{ not matrix.os.install_node_20_ubuntu }}
         run: apt-get update
 
+      # Node.js 20 is required by actions/download-artifact.
+      # TODO(strager): Bake this step into the Docker image.
+      - name: install Node.js 20 on Ubuntu
+        if: ${{ matrix.os.install_node_20_ubuntu }}
+        run: |
+          curl -sL https://deb.nodesource.com/setup_18.x -o nodesource_setup.sh
+          bash nodesource_setup.sh
+          apt-get install nodejs
+        shell: bash
+
       - uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a # v3.0.2
         with:
           name: quick-lint-js-deb-${{ matrix.os.arch }}-${{ github.sha }}