Update actions/checkout action to v6 (#173)

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

Author: renovate[bot]

.github/workflows/lint.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
     - name: Checkout mis
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Set up Python 3.10
       uses: actions/setup-python@v6

.github/workflows/publish.yml

@@ -18,7 +18,7 @@ jobs:
             id-token: write
         steps:
         - name: Check out mis
-          uses: actions/checkout@v5
+          uses: actions/checkout@v6
           with:
             ref: ${{ github.ref }}
         - name: Set up Python
@@ -49,7 +49,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
         - name: Checkout mis
-          uses: actions/checkout@v5
+          uses: actions/checkout@v6
         - name: Install JetBrains Mono font
           run: |
             sudo apt install -y wget unzip fontconfig

.github/workflows/test.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - name: Checkout mis
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:
@@ -59,7 +59,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - name: Checkout mis
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:
@@ -80,7 +80,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - name: Checkout MIS
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:
@@ -101,7 +101,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout mis
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6
         with:
@@ -125,7 +125,7 @@ jobs:
         python-version: ["3.10"]
     steps:
       - name: Checkout mis
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6
         with: