license expression in package.json obtains other rather than nil

https://docs.npmjs.com/files/package.json#license can be a SPDX
license expression rather than a SPDX license id. If expression
found, makes sense to return other license rather than nil from
package. So add space, plus, and parens to character class match
as those can be part of a license expression.

lib/licensee/matchers/npm_bower.rb

@@ -4,7 +4,7 @@ module Licensee
       # While we could parse the package.json or bower.json file, prefer
       # a lenient regex for speed and security. Moar parsing moar problems.
       LICENSE_REGEX = /
-        \s*[\"\']license[\"\']\s*\:\s*[\'\"]([a-z\-0-9\.]+)[\'\"],?\s*
+        \s*[\"\']license[\"\']\s*\:\s*[\'\"]([a-z\-0-9\.+ ()]+)[\'\"],?\s*
       /ix
 
       private

spec/fixtures/npm-license-expression/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "fake-package"
+  "description": "Fake package available under various licenses",
+  "license": "(MIT OR Apache-2.0 OR AGPL-3.0+)",
+  "version": "0.1"
+}

spec/integration_spec.rb

@@ -177,6 +177,15 @@ RSpec.describe 'integration test' do
             expect(subject.license).to eql(license)
           end
         end
+
+        context 'with package.json license expression' do
+          let(:fixture) { 'npm-license-expression' }
+          let(:arguments) { { detect_packages: true } }
+
+          it 'matches other' do
+            expect(subject.license).to eql(other_license)
+          end
+        end
       end
 
       context 'with the license file stubbed' do