Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/lint.yml

@@ -9,7 +9,7 @@ jobs:
     name: YAML
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - run: pip install yamllint
       - run: yamllint -s -f github .

.github/workflows/test.yml

@@ -29,7 +29,7 @@ jobs:
     name: Single Key
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: TheHackerApp/setup-ssh
         uses: ./
@@ -43,7 +43,7 @@ jobs:
     name: Multiple Keys
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: TheHackerApp/setup-ssh
         uses: ./
@@ -61,7 +61,7 @@ jobs:
     name: known_hosts Empty (No Host)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: TheHackerApp/setup-ssh
         uses: ./
@@ -75,7 +75,7 @@ jobs:
     name: known_hosts Single Host
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: TheHackerApp/setup-ssh
         uses: ./
@@ -90,7 +90,7 @@ jobs:
     name: known_hosts Multiple Hosts
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: TheHackerApp/setup-ssh
         uses: ./