Bump actions/checkout from 2 to 4

.github/workflows/CI.yml

@@ -24,14 +24,14 @@ jobs:
     name: Code Format
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: jcheckstyle
         run: ./sbt jcheckStyle
   test_jdk21:
     name: Test JDK21
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
@@ -49,7 +49,7 @@ jobs:
     name: Test JDK17
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
@@ -67,7 +67,7 @@ jobs:
     name: Test JDK11
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
@@ -85,7 +85,7 @@ jobs:
     name: Test JDK8
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     name: Release
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 10000
       # Fetch all tags so that sbt-dynver can find the previous release version

.github/workflows/snapshot.yml

@@ -16,7 +16,7 @@ jobs:
     name: Publish snapshots
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 10000
       # Fetch all tags so that sbt-dynver can find the previous release version