add security headers

_headers

@@ -0,0 +1,12 @@
+/
+  Content-Security-Policy: default-src 'self' michivonah.ch; script-src 'self' unpkg.com; style-src 'self' unpkg.com michivonah.ch fonts.googleapis.com; img-src 'self' michivonah.ch; font-src 'self' unpkg.com fonts.googleapis.com fonts.gstatic.com; upgrade-insecure-requests
+  Permissions-Policy: accelerometer=(), autoplay=(), display-capture=(), camera=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), payment=(), usb=()
+  Referrer-Policy: origin
+  Strict-Transport-Security: max-age=31536000; includeSubDomains
+  X-Content-Type-Options: nosniff
+  X-Frame-Options: DENY
+  X-XSS-Protection: 1; mode=block
+  Cross-Origin-Embedder-Policy: require-corp
+  Cross-Origin-Opener-Policy: same-origin
+  Cross-Origin-Resource-Policy: same-origin
+  Access-Control-Allow-Origin: *