Remove square brackets from branch names

common/lib/dependabot/pull_request_creator/branch_namer.rb

@@ -27,7 +27,11 @@ def new_branch_name
               elsif dependencies.count > 1 && updating_a_dependency_set?
                 dependency_set.fetch(:group)
               else
-                dependencies.map(&:name).join("-and-").tr(":", "-").tr("@", "")
+                dependencies.
+                  map(&:name).
+                  join("-and-").
+                  tr(":[]", "-").
+                  tr("@", "")
               end
 
             dep = dependencies.first
@@ -42,6 +46,7 @@ def new_branch_name
           end
 
         branch_name = File.join(prefixes, @name).
+                      gsub(/-+/, "-").
                       gsub(%r{/\.}, "/dot-").
                       gsub(%r{/\.}, "/dot-")
 

common/spec/dependabot/pull_request_creator/branch_namer_spec.rb

@@ -290,6 +290,23 @@
       end
     end
 
+    context "with square brackets in the name" do
+      let(:dependency) do
+        Dependabot::Dependency.new(
+          name: "werkzeug[watchdog]",
+          version: "0.16.0",
+          previous_version: "0.15.0",
+          package_manager: "pip",
+          requirements: []
+        )
+      end
+
+      it "replaces the brackets with hyphens" do
+        expect(new_branch_name).
+          to eq("dependabot/pip/werkzeug-watchdog-0.16.0")
+      end
+    end
+
     context "with a requirement only" do
       let(:previous_version) { nil }
       let(:requirements) do