Add .clangd to .gitignore

Bug: None
Change-Id: I07496ecaaac72d4bb43cb67baa364abe6df82693
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158528
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Rasmus Brandt <brandtr@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29629}
diff --git a/.gitignore b/.gitignore
index 9d65fb0..8c7582c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,6 +27,7 @@
 *~
 .*.sw?
 .cipd
+.clangd
 .classpath
 .cproject
 .gdb_history