Merge pull request #64 from marcel-wiedemeier/patch-7

Update _headers

docs/_headers

@@ -6,6 +6,6 @@
   X-Frame-Options: DENY
   X-XSS-Protection: 1; mode=block
   referrer-policy: no-referrer, strict-origin-when-cross-origin
-  Strict-Transport-Security: max-age=31536000 ; includeSubDomains
+  Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
   content-security-policy: default-src 'none'; script-src 'self' 'unsafe-inline' ajax.googleapis.com cdn.syndication.twimg.com; connect-src 'self'; img-src 'self' data: pbs.twimg.com *.travis-ci.org travis-ci.org; style-src 'self' 'unsafe-inline' fonts.googleapis.com; font-src 'self' data: fonts.gstatic.com; object-src 'none'; frame-ancestors 'none';report-uri https://unic.report-uri.com/r/d/csp/enforce; report-to csp; base-uri 'none'; form-action 'none'; manifest-src 'self'
   Report-To: { "url": "https://unic.report-uri.com/r/d/csp/reportOnly", "group": "cspro", "max-age": 10886400 }, { "url": "https://unic.report-uri.com/r/d/csp/enforce", "group": "csp","max-age": 10886400 }