Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/go-ci.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
         with:
           submodules: recursive
       - name: Set up Go

.github/workflows/scip.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     container: sourcegraph/scip-go
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v6
       - name: Get src-cli
         run: curl -L https://sourcegraph.com/.api/src-cli/src_linux_amd64 -o /usr/local/bin/src;
           chmod +x /usr/local/bin/src