Bump actions/checkout from 5 to 6 (#280)

Author: dependabot[bot]

.github/workflows/run-tests.yml

@@ -11,7 +11,7 @@ jobs:
           - 2021.3.16f1
           - 2020.3.43f1
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ inputs.ref }}
 
@@ -52,7 +52,7 @@ jobs:
           - { version: "2021.3.16f1", changeset: "4016570cf34f" }
           - { version: "2020.3.43f1", changeset: "75bff06b76bf" }
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ inputs.ref }}
 
@@ -90,7 +90,7 @@ jobs:
           - { version: "2021.3.16f1", changeset: "4016570cf34f" }
           - { version: "2020.3.43f1", changeset: "75bff06b76bf" }
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ inputs.ref }}
 

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Install node package, `unity-verify-code`
       run: npm install --global unity-verify-code