test: Remove support for Node 18 (#365)

Co-authored-by: Muhammad Anas <muhammad.anas@arbisoft.com>

.github/workflows/ci.yml

@@ -11,9 +11,6 @@ on:
 jobs:
   tests:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        node: [18.15, 20]
 
     steps:
     - name: Checkout
@@ -24,7 +21,7 @@ jobs:
       uses: actions/setup-node@v4
 # Because of node 18 bug (https://github.com/nodejs/node/issues/47563), Pinning node version 18.15 until the next release of node
       with:
-        node-version: ${{ matrix.node }}
+        node-version-file: '.nvmrc'
 
     - name: Install dependencies
       run: npm ci