ci: update actions/checkout to v4 and remove explicit name

Signed-off-by: Martin Kröning <[email protected]>

Author: mkroening

.github/workflows/build.yml

@@ -16,8 +16,7 @@ jobs:
     name: Check
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout sources
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1
@@ -35,8 +34,7 @@ jobs:
     name: Test Suite
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout sources
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1
@@ -54,8 +52,7 @@ jobs:
     name: Test Suite (unstable)
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout sources
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Install nightly toolchain
         uses: actions-rs/toolchain@v1
@@ -74,8 +71,7 @@ jobs:
     name: Test Suite (very_unstable)
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout sources
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Install nightly toolchain
         uses: actions-rs/toolchain@v1
@@ -95,8 +91,7 @@ jobs:
     name: Lints
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout sources
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1