CI: Update first-party GitHub Actions to v4

GitHub Actions has deprecated actions based on node16. The v4 actions
are based on node20. Replace first-party v2/v3 actions with their v4
counterparts.

GitHub Actions has deprecated actions based on node12 and forces them to
run on node16, which is also deprecated. Update to v4 actions to avoid
warnings on CI.

See:
https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/
https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

.github/workflows/crowdin_upload.yml

@@ -11,7 +11,7 @@ jobs:
     if: github.repository_owner == 'obsproject'
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 100
       - name: Upload US English Language Files 🇺🇸

.github/workflows/generate_docs.yml

@@ -18,7 +18,7 @@ jobs:
       IS_CI: "true"
     steps:
       - name: 'Checkout'
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           path: ${{ github.workspace }}/obs-websocket
       - name: 'Generate docs'

.github/workflows/lint.yml

@@ -15,7 +15,7 @@ jobs:
     if: contains(github.event.head_commit.message, '[skip ci]') != true
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Generate docs
         run: cd docs && ./build_docs.sh
       - name: Run markdownlint-cli