Bump actions/checkout from 2 to 2.3.4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 2.3.4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v2.3.4)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.3.4
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v1
         with:
@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/setup-python@v2
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - run: sudo apt install -y gettext aspell libenchant-dev
       - uses: actions/[email protected]
         with:
@@ -49,7 +49,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/setup-python@v2
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: actions/[email protected]
         with:
           path: ~/.cache/pip