Bump actions/checkout from 2 to 2.3.4 (#7269)

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]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/gradle-wrapper-validation.yml

@@ -6,5 +6,5 @@ jobs:
     name: "Validation"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: gradle/[email protected]

.github/workflows/gradle_branch.yml

@@ -12,7 +12,7 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up JDK 8
       uses: actions/setup-java@v2
       with:

.github/workflows/gradle_jdk11.yml

@@ -14,7 +14,7 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up JDK 11
       uses: actions/setup-java@v2
       with:

.github/workflows/gradle_pr.yml

@@ -12,7 +12,7 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up JDK 8
       uses: actions/setup-java@v2
       with:

.github/workflows/gradle_release.yml

@@ -17,7 +17,7 @@ jobs:
     env:
       CI_BUILD_NUMBER: ${{ github.run_number }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up JDK 8
       uses: actions/setup-java@v2
       with:

.github/workflows/gradle_snapshot.yml

@@ -15,7 +15,7 @@ jobs:
       # ------------------------------------------------------------------------------ 
       CI_BUILD_NUMBER: ${{ github.run_number }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up JDK 8
       uses: actions/setup-java@v2
       with: