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.yaml

@@ -9,7 +9,7 @@ jobs:
         scala: [2.13.5, 2.12.13]
         nodejs: [14.16.0, 12.21.0, 10.24.0]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: olafurpg/setup-scala@v10
         with:
           java-version: [email protected]

.github/workflows/format.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: olafurpg/setup-scala@v10
       - name: Check Scalafmt/Scaladoc
         run: sbt scalafmtSbtCheck scalafmtCheck test:scalafmtCheck nodejs_v14/doc core/doc