feat!: removes Node.js 18 as it reached EOL (#742)

Author: timbru31

.github/workflows/buildx.yml

@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version: [3.2, 3.3, 3.4]
-        node-version: [18, 20, 22]
+        node-version: [20, 22]
         variant: [default, slim, alpine]
         include:
           - variant: default
@@ -32,7 +32,6 @@ jobs:
         id: nodename
         run: |
           case "${{ matrix.node-version }}" in
-            "18") echo "codename=hydrogen" >> $GITHUB_OUTPUT ;;
             "20") echo "codename=iron" >> $GITHUB_OUTPUT ;;
             "22") echo "codename=jod" >> $GITHUB_OUTPUT ;;
             "24") echo "codename=krypton" >> $GITHUB_OUTPUT ;;

.github/workflows/dockerimage.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version: [3.2, 3.3, 3.4]
-        node-version: [18, 20, 22]
+        node-version: [20, 22]
         variant: [default, slim, alpine]
 
     steps: