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](https://github.com/actions/checkout/compare/v2...v2.3.4)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/brakeman-analysis.yml

@@ -17,7 +17,7 @@ jobs:
     steps:
     # Checkout the repository to the GitHub Actions runner
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
 
     # Customize the ruby version depending on your needs
     - name: Setup Ruby

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
   contributors:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
       - name: Install ruby version specified in .ruby-version
         uses: ruby/setup-ruby@v1
         with:
@@ -53,7 +53,7 @@ jobs:
 
     steps:
       - name: Checkout this repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.3.4
 
       - name: Configure sysctl limits
         run: |