update to go1.20.13

go1.20.13 (released 2024-01-09) includes fixes to the runtime and the crypto/tls
package. See the Go 1.20.13 milestone on our issue tracker for details:

- https://github.com/golang/go/issues?q=milestone%3AGo1.20.13+label%3ACherryPickApproved
- full diff: https://github.com/golang/go/compare/go1.20.12...go1.20.13

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

.github/workflows/test.yml

@@ -63,7 +63,7 @@ jobs:
         name: Set up Go
         uses: actions/setup-go@v3
         with:
-          go-version: 1.20.12
+          go-version: 1.20.13
       -
         name: Test
         run: |