Add regex validation on alias name

ee/app/models/project_alias.rb

@@ -4,5 +4,11 @@ class ProjectAlias < ApplicationRecord
   belongs_to :project
 
   validates :project, presence: true
-  validates :name, presence: true, uniqueness: true
+  validates :name,
+    presence: true,
+    uniqueness: true,
+    format: {
+      with: ::Gitlab::PathRegex.project_path_format_regex,
+      message: ::Gitlab::PathRegex.project_path_format_message
+    }
 end

ee/spec/models/project_alias_spec.rb

@@ -10,4 +10,7 @@ describe ProjectAlias do
   it { is_expected.to validate_presence_of(:project) }
   it { is_expected.to validate_presence_of(:name) }
   it { is_expected.to validate_uniqueness_of(:name) }
+  it { is_expected.not_to allow_value('/foo').for(:name) }
+  it { is_expected.not_to allow_value('foo/foo').for(:name) }
+  it { is_expected.not_to allow_value('foo.git').for(:name) }
 end