Fix deprecations added in fbedce9

Author: timdorr

src/index.js

@@ -31,7 +31,7 @@ const processor = postcss.plugin( 'modules-extract-imports', function ( options
 
     // If we've found any imports, insert or append :import rules
     let existingImports = {};
-    css.eachRule(rule => {
+    css.walkRules(rule => {
       let matches = icssImport.exec(rule.selector);
       if (matches) {
         let [/*match*/, doubleQuotePath, singleQuotePath] = matches;
@@ -45,15 +45,15 @@ const processor = postcss.plugin( 'modules-extract-imports', function ( options
       if (!rule) {
         rule = postcss.rule( {
           selector: `:import("${path}")`,
-          after: "\n"
+          raws: { after: "\n" }
         } );
         css.prepend( rule );
       }
       Object.keys( imports[path] ).forEach( importedSymbol => {
         rule.push(postcss.decl( {
           value: importedSymbol,
           prop: imports[path][importedSymbol],
-          before: "\n  ",
+          raws: { before: "\n  " },
           _autoprefixerDisabled: true
         } ) );
       } );