chore: Upgrade to Go 1.19 (#3617)

This is required as part of #3505.

coderd/workspaceapps_test.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"net/http"
 	"testing"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/stretchr/testify/assert"
@@ -27,6 +28,7 @@ func TestWorkspaceAppsProxyPath(t *testing.T) {
 	ln, err := net.Listen("tcp", ":0")
 	require.NoError(t, err)
 	server := http.Server{
+		ReadHeaderTimeout: time.Minute,
 		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			_, err := r.Cookie(codersdk.SessionTokenKey)
 			assert.ErrorIs(t, err, http.ErrNoCookie)