refactor: updated to Node version 20 (#675)

* refactor: updated to Node version 20

* Update action.yml

Author: mfranzke

.github/actions/npm-cache/action.yml

@@ -8,7 +8,7 @@ runs:
       # https://github.com/actions/setup-node
       uses: actions/setup-node@v3
       with:
-        node-version: 18
+        node-version: 20
 
     - name: Display node and npm version
       shell: bash

.nvmrc

@@ -1 +1 @@
-18
+20