Bump actions/checkout from 6 to 7 (#323)

Author: dependabot[bot]

.github/workflows/continuous_integration.yml

@@ -16,7 +16,7 @@ jobs:
         os: [macos-latest, ubuntu-latest]
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: fish-actions/install-fish@v1.1.0
 
       - uses: fish-actions/fisher@v1
@@ -41,7 +41,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - uses: fish-actions/install-fish@v1
 
@@ -52,7 +52,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - uses: fish-actions/install-fish@v1
 
@@ -62,7 +62,7 @@ jobs:
   prettier:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: actionsx/prettier@v3
         with:
           args: --check .