Make git-hooks track with origin/main

This way when you run `git submodule update third-party/git-hooks` it
will actually update to the HEAD commit of that branch. No need to
manually updated the submodule to the latest revision.

Bug: b/187094215
Change-Id: Id0e1cf15c15ae73e00e3481d1d3532fe541c0070
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/58590
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Sean Risser <srisser@google.com>
Commit-Queue: Sean Risser <srisser@google.com>
diff --git a/.gitmodules b/.gitmodules
index 1526a1c..9a757e0 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -25,3 +25,5 @@
 [submodule "third_party/git-hooks"]
 	path = third_party/git-hooks
 	url = https://swiftshader.googlesource.com/git-hooks
+[submodule "third_party/git-hooks/"]
+	branch = origin/master