Fix handling of @charset in media imports (#453)

Fixes #448

index.js

@@ -68,7 +68,7 @@ function AtImport(options) {
 
       function applyMedia(bundle) {
         bundle.forEach(stmt => {
-          if (!stmt.media.length) return
+          if (!stmt.media.length || stmt.type === "charset") return
           if (stmt.type === "import") {
             stmt.node.params = `${stmt.fullUri} ${stmt.media.join(", ")}`
           } else if (stmt.type === "media")

test/fixtures/imports/charset-content.css

@@ -0,0 +1,2 @@
+@charset "UTF-8";
+.charset-content {}

test/fixtures/media-charset.css

@@ -0,0 +1 @@
+@import "charset-content" level-1;

test/fixtures/media-charset.expected.css

@@ -0,0 +1,4 @@
+@charset "UTF-8";
+@media level-1{
+.charset-content {}
+}

test/media.js

@@ -19,4 +19,10 @@ test(
   "media-content"
 )
 
+test(
+  "should resolve media query imports with charset",
+  checkFixture,
+  "media-charset"
+)
+
 test("should join correctly media queries", checkFixture, "media-join")