Update actions/checkout requirement to v2.3.4

Updates the requirements on [actions/checkout](https://github.com/actions/checkout) to permit the latest version.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/commits/5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f)

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

.github/workflows/docker.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Checkout source
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2.3.4
     - name: Poke config
       run: |
         cp config/example.storage.yml config/storage.yml

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Check out code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup ruby
       uses: actions/setup-ruby@v1
       with:
@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Check out code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup ruby
       uses: actions/setup-ruby@v1
       with:
@@ -59,7 +59,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Check out code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup ruby
       uses: actions/setup-ruby@v1
       with:
@@ -94,7 +94,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Check out code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup ruby
       uses: actions/setup-ruby@v1
       with:

.github/workflows/tests.yml

@@ -15,7 +15,7 @@ jobs:
       OPENSTREETMAP_MEMCACHE_SERVERS: 127.0.0.1
     steps:
     - name: Checkout source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup ruby
       uses: actions/setup-ruby@v1
       with: