Update actions/checkout action to v4 (#48)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/PR.yml

@@ -12,7 +12,7 @@ jobs:
 
       steps:
          -  name: Checkout the repo
-            uses: actions/checkout@v3
+            uses: actions/checkout@v4
 
          -  name: Setup JDK
             uses: actions/setup-java@v3

.github/workflows/master.yml

@@ -13,7 +13,7 @@ jobs:
       runs-on: ubuntu-latest
       steps:
          -  name: Checkout the repo
-            uses: actions/checkout@v3
+            uses: actions/checkout@v4
             with:
                fetch-depth: 0
 

.github/workflows/release.yml

@@ -17,7 +17,7 @@ jobs:
 
       steps:
          -  name: Checkout the repo
-            uses: actions/checkout@v3
+            uses: actions/checkout@v4
             with:
                fetch-depth: 0
                ref: ${{ github.event.inputs.branch }}