Validate email of git configuration

This regex matches a basic email pattern.

Change-Id: I7196a97db325c73f3b88462b69edc2ddc7d0fbce

scripts/check-repo.sh

@@ -20,6 +20,20 @@ if ! command -v git &>/dev/null; then
   throw "git not installed."
 fi
 
+# Retrieve git email.
+GIT_EMAIL=$(git config user.email)
+
+# Check if email is set.
+if [ -z "$GIT_EMAIL" ]; then
+  throw "Git email is not set."
+fi
+
+# Validate email using a regex.
+# This regex matches a basic email pattern.
+if ! [[ "$GIT_EMAIL" =~ ^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$ ]]; then
+  throw "Git email '$GIT_EMAIL' is not valid."
+fi
+
 # 1. Sleep for a random number of milliseconds
 # The time interval is important to reduce unintended network traffic.
 ((CURRENT_STEP++))