Fix macOS compile error, maybe fix test failure.

Author: kring

CesiumCurl/src/CurlAssetAccessor.cpp

@@ -410,10 +410,10 @@ Future<std::shared_ptr<IAssetRequest>> CurlAssetAccessor::get(
 
 namespace {
 
-constexpr std::string_view fileProtocol("file:");
+constexpr std::string_view fileScheme("file:");
 
 bool isFile(const std::string& url) {
-  return Uri(url).getScheme() == fileProtocol;
+  return Uri(url).getScheme() == fileScheme;
 }
 
 std::string convertFileUriToFilename(const std::string& url) {

CesiumCurl/test/TestCurlAssetAccessor.cpp

@@ -47,7 +47,7 @@ TEST_CASE("CurlAssetAccessor") {
           pAssetAccessor
               ->get(
                   asyncSystem,
-                  std::format("http://127.0.01:{}/test/some/file.txt", port),
+                  fmt::format("http://127.0.01:{}/test/some/file.txt", port),
                   {})
               .waitInMainThread();