allow pass a client certificate to OTLPLogExporter

Author: xman1979

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/_log_exporter/__init__.py

@@ -67,6 +67,7 @@ def __init__(
         self,
         endpoint: Optional[str] = None,
         certificate_file: Optional[str] = None,
+        client_certificate_file: Optional[str] = None,
         headers: Optional[Dict[str, str]] = None,
         timeout: Optional[int] = None,
         compression: Optional[Compression] = None,
@@ -82,6 +83,7 @@ def __init__(
             OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE,
             environ.get(OTEL_EXPORTER_OTLP_CERTIFICATE, True),
         )
+        self._client_certificate_file = certificate_file
         headers_string = environ.get(
             OTEL_EXPORTER_OTLP_LOGS_HEADERS,
             environ.get(OTEL_EXPORTER_OTLP_HEADERS, ""),
@@ -118,6 +120,7 @@ def _export(self, serialized_data: bytes):
             data=data,
             verify=self._certificate_file,
             timeout=self._timeout,
+            cert=self._client_certificate_file,
         )
 
     @staticmethod