add protobuf as tool_requires

recipes/opentelemetry-cpp/all/conanfile.py

@@ -66,16 +66,16 @@ def requirements(self):
             self.requires("boost/1.80.0")
 
     def validate(self):
-        if Version(self.version) == "1.0.1" and self.info.settings.arch != "x86_64":
-            raise ConanInvalidConfiguration(f"{self.ref} doesn't support architecture : {self.info.settings.arch}")
-
         if self.info.settings.compiler.cppstd:
             check_min_cppstd(self, self._minimum_cpp_standard)
         check_min_vs(self, "192")
 
         if self.settings.os != "Linux" and self.options.shared:
             raise ConanInvalidConfiguration(f"{self.ref} supports building shared libraries only on Linux")
 
+    def build_requirements(self):
+        self.tool_requires("protobuf/3.21.4")
+
     def _create_cmake_module_variables(self, module_file):
         content = textwrap.dedent("""\
             set(OPENTELEMETRY_CPP_INCLUDE_DIRS ${opentelemetry-cpp_INCLUDE_DIRS}