fix(rule): add default UserAgent and Accept Header (#116)

Author: azu

src/no-dead-link.js

@@ -78,6 +78,13 @@ async function isAliveURI(uri, method = 'HEAD') {
     // to avoid the zlib's "unexpected end of file" error
     // https://github.com/request/request/issues/2045
     compress: false,
+    // Some website require UserAgent and Accept header
+    // to avoid ECONNRESET error
+    // https://github.com/textlint-rule/textlint-rule-no-dead-link/issues/111
+    headers: {
+      'User-Agent': 'textlint-rule-no-dead-link/1.0',
+      'Accept': '*/*'
+    },
     // Use `manual` redirect behaviour to get HTTP redirect status code
     // and see what kind of redirect is occurring
     redirect: 'manual',

test/no-dead-link.js

@@ -15,6 +15,8 @@ tester.run('no-dead-link', rule, {
     'should be able to check a URL in Markdown: https://example.com/',
     'should success with retrying on error: [npm results for textlint](https://www.npmjs.com/search?q=textlint)',
     'should treat 200 OK as alive: https://httpstat.us/200',
+    'should treat 200 OK. It require User-Agent: Navigate to [MySQL distribution](https://dev.mysql.com/downloads/mysql/) to install MySQL `5.7`.',
+    'should treat 200 OK. It require User-Agent: <https://tools.ietf.org/html/rfc6749>',
     {
       text:
         'should be able to check a URL in a plain text: https://example.com/',