Add mutext around render.Respond override

- This is an attempt to fix a race condition which only occurs in CI

router.go

@@ -4,11 +4,14 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"sync"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/render"
 )
 
+var respondMtx sync.Mutex
+
 // HTMLer allows for easily represending reponses as HTML strings when accepted content
 // type is text/html
 type HTMLer interface {
@@ -17,6 +20,7 @@ type HTMLer interface {
 
 // Create API routes on the given router
 func (a *API[T]) Route(r chi.Router) {
+	respondMtx.Lock()
 	render.Respond = func(w http.ResponseWriter, r *http.Request, v interface{}) {
 		if render.GetAcceptedContentType(r) == render.ContentTypeHTML {
 			htmler, ok := v.(HTMLer)
@@ -28,6 +32,7 @@ func (a *API[T]) Route(r chi.Router) {
 
 		render.DefaultResponder(w, r, v)
 	}
+	respondMtx.Unlock()
 
 	r.Route(a.base, func(r chi.Router) {
 		// Only set these middleware for root-level API