ci: execute CI for PRs on earlgrey-hwe

Signed-off-by: Chris Frantz <cfrantz@google.com>

.github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c6dff8f..82dace0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,7 +6,7 @@
   push:
     branches: [ main, develop ]
   pull_request:
-    branches: [ main ]
+    branches: [ main, earlgrey-hwe ]
 
 env:
   CARGO_TERM_COLOR: always