ci: fix typo in cache

Author: lread

.github/workflows/unit-test.yml

@@ -78,8 +78,8 @@ jobs:
       uses: actions/cache@v3
       with:
         path: ./node_modules
-        key: $${ runner.os }}-node-${{ hashFiles('package-lock.json') }}
-        restore-keys: $${ runner.os }}-node-
+        key: ${{ runner.os }}-node-${{ hashFiles('package-lock.json') }}
+        restore-keys: ${{ runner.os }}-node-
 
     #
     # Setup Java