fix: gh actions that run on main (#3550)

## About the changes
These also need to be migrated to node 18

.github/workflows/build_coverage.yaml

@@ -15,7 +15,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x]
+        node-version: [18.x]
     services:
       # Label used to access the service container
       postgres:

.github/workflows/update_contributors.yaml

@@ -10,10 +10,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-    - name: Use Node.js 16.x
+      - name: Use Node.js 18.x
         uses: actions/setup-node@v3
         with:
-        node-version: 16.x
+          node-version: 18.x
       - uses: actions/checkout@master
         with:
           repository: sighphyre/svg-contributors