golangci-lint: set go version to prevent fallback to go1.17

GolangCI-lint attempts to deduct the Go version to lint for through the
go version specified in go.mod, which we don't have, and therefore it
falls back to go1.17 semantics:

    level=warning msg="[linters_context] copyloopvar: this linter is disabled because the Go version (1.17) of your project is lower than Go 1.22

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

.golangci.yml

@@ -41,6 +41,9 @@ linters:
     - errcheck
 
 run:
+  # prevent golangci-lint from deducting the go version to lint for through go.mod,
+  # which causes it to fallback to go1.17 semantics.
+  go: "1.23.2"
   timeout: 5m
 
 linters-settings: