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](5a4ac9002d)

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

.github/workflows/build.yml

@@ -9,7 +9,7 @@ jobs:
       matrix:
         node-version: [10.x, 12.x]
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2.3.4
 
     - name: Setup Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v1

.github/workflows/e2e.yml

@@ -9,7 +9,7 @@ jobs:
       matrix:
         node-version: [12.x]
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2.3.4
 
     - name: Setup Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v1

.github/workflows/release-preview-publish.yml

@@ -9,7 +9,7 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2.3.4
     - name: Setup Node.js
       uses: actions/setup-node@v1
       with:

.github/workflows/release-publish.yml

@@ -8,7 +8,7 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - uses: fregante/setup-git-user@v1
 
     - name: Setup Node.js