decompressor: Set window_bits default to 15 (#14194)

The current default window_bits of 12 for the decompressor causes issues while decompressing responses
which were compressed by a compressor with window_size greater than 12.

Default window_bits to 15 to not run into any surprises when the decompressor is deployed with defaults.

Signed-off-by: Bharath Vedartham <vedabharath12345@gmail.com>

Mirrored from https://github.com/envoyproxy/envoy @ e6700e5257c2da1817145a405b2440b90c3d3747

envoy/extensions/compression/gzip/decompressor/v3/gzip.proto

@@ -20,8 +20,8 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 message Gzip {
   // Value from 9 to 15 that represents the base two logarithmic of the decompressor's window size.
   // The decompression window size needs to be equal or larger than the compression window size.
-  // The default is 12 to match the default in the
-  // :ref:`gzip compressor <envoy_api_field_extensions.compression.gzip.compressor.v3.Gzip.window_bits>`.
+  // The default window size is 15.
+  // This is so that the decompressor can decompress a response compressed by a compressor with any compression window size.
   // For more details about this parameter, please refer to `zlib manual <https://www.zlib.net/manual.html>`_ > inflateInit2.
   google.protobuf.UInt32Value window_bits = 1 [(validate.rules).uint32 = {lte: 15 gte: 9}];