CI: Update deprecated GitHub Actions (#6822)

## Problem

We use a bunch of deprecated actions.
See https://github.com/neondatabase/neon/actions/runs/7958569728
(Annotations section)

```
Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3, actions/setup-java@v3, actions/cache@v3, actions/github-script@v6. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.
```

## Summary of changes
- `actions/cache@v3` -> `actions/cache@v4`
- `actions/checkout@v3` -> `actions/checkout@v4`
- `actions/github-script@v6` -> `actions/github-script@v7`
- `actions/setup-java@v3` -> `actions/setup-java@v4`
- `actions/upload-artifact@v3` -> `actions/upload-artifact@v4`

.github/workflows/trigger-e2e-tests.yml

@@ -9,7 +9,7 @@ on:
 defaults:
   run:
     shell: bash -euxo pipefail {0}
-    
+
 env:
   # A concurrency group that we use for e2e-tests runs, matches `concurrency.group` above with `github.repository` as a prefix
   E2E_CONCURRENCY_GROUP: ${{ github.repository }}-e2e-tests-${{ github.ref_name }}-${{ github.ref_name == 'main' && github.sha || 'anysha' }}
@@ -37,7 +37,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
@@ -115,4 +115,3 @@ jobs:
                 \"concurrency_group\": \"${{ env.E2E_CONCURRENCY_GROUP }}\"
               }
             }"
-