[Issue open-telemetry#1107] Change doc-string for compression argument and modify Enum value from DEFAULT to NO_COMPRESSION

Author: wilguo

exporter/opentelemetry-exporter-otlp/src/opentelemetry/exporter/otlp/exporter.py

@@ -47,7 +47,7 @@
 
 
 class GRPCCompression(enum.Enum):
-    DEFAULT = 0
+    NO_COMPRESSION = 0
     GZIP = 1
 
 
@@ -138,14 +138,14 @@ def __init__(
         endpoint: str = "localhost:55680",
         credentials: ChannelCredentials = None,
         metadata: Optional[Tuple[Any]] = None,
-        compression: enum.Enum = GRPCCompression.DEFAULT,
+        compression: GRPCCompression = GRPCCompression.NO_COMPRESSION,
     ):
         super().__init__()
 
         self._metadata = metadata
         self._collector_span_kwargs = None
 
-        if compression is GRPCCompression.DEFAULT:
+        if compression is GRPCCompression.NO_COMPRESSION:
             compression_algorithm = Compression.NoCompression
         elif compression is GRPCCompression.GZIP:
             compression_algorithm = Compression.Gzip