Set Node version in a single place (#6534)

This should make it much easier to update.  Also use 18.15.0
specifically since that is what VS Code ships with.

Additionally, it fixes the post-install script being skipped due to
a Yarn v1 bug that happens when Yarn installs node-gyp, which
it does because 18.18 onward stopped bundling node-gyp.

.github/workflows/release.yaml

@@ -35,10 +35,10 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v4
 
-      - name: Install Node.js v18
+      - name: Install Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: "18.15.0"
+          node-version-file: .node-version
 
       - name: Install development tools
         run: |
@@ -128,7 +128,6 @@ jobs:
       PKG_CONFIG_PATH: ${{ format('/usr/lib/{0}/pkgconfig', matrix.prefix) }}
       TARGET_ARCH: ${{ matrix.apt_arch }}
       npm_config_arch: ${{ matrix.npm_arch }}
-      NODE_VERSION: v18.15.0
       # Not building from source results in an x86_64 argon2, as if
       # npm_config_arch is being ignored.
       npm_config_build_from_source: true
@@ -137,10 +136,10 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v4
 
-      - name: Install Node.js v18
+      - name: Install Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: "18.15.0"
+          node-version-file: .node-version
 
       - name: Install cross-compiler and system dependencies
         run: |
@@ -174,8 +173,9 @@ jobs:
 
       - name: Replace node with cross-compile equivalent
         run: |
-          wget https://nodejs.org/dist/${NODE_VERSION}/node-${NODE_VERSION}-linux-${npm_config_arch}.tar.xz
-          tar -xf node-${NODE_VERSION}-linux-${npm_config_arch}.tar.xz node-${NODE_VERSION}-linux-${npm_config_arch}/bin/node --strip-components=2
+          node_version=$(node --version)
+          wget https://nodejs.org/dist/${node_version}/node-${node_version}-linux-${npm_config_arch}.tar.xz
+          tar -xf node-${node_version}-linux-${npm_config_arch}.tar.xz node-${node_version}-linux-${npm_config_arch}/bin/node --strip-components=2
           mv ./node ./release-standalone/lib/node
 
       # NOTE@jsjoeio - we do this so we can strip out the v
@@ -205,10 +205,10 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v4
 
-      - name: Install Node.js v18
+      - name: Install Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: "18.15.0"
+          node-version-file: .node-version
 
       - name: Install nfpm
         run: |