Rename GetBindGroupLayout's argument group->groupIndex

This is to follow upstream webgpu.h changes.

Bug: dawn:22
Change-Id: I976d1394a31a47870a73ed834137ce99047675bd
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/18540
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
diff --git a/dawn.json b/dawn.json
index 6973a94..bfb03aa 100644
--- a/dawn.json
+++ b/dawn.json
@@ -480,7 +480,7 @@
                 "name": "get bind group layout",
                 "returns": "bind group layout",
                 "args": [
-                    {"name": "group", "type": "uint32_t"}
+                    {"name": "group index", "type": "uint32_t"}
                 ]
             }
         ]
@@ -1213,7 +1213,7 @@
                 "name": "get bind group layout",
                 "returns": "bind group layout",
                 "args": [
-                    {"name": "group", "type": "uint32_t"}
+                    {"name": "group index", "type": "uint32_t"}
                 ]
             }
         ]