restore CSS sourcemap support (#770)

* fix: restore CSS sourcemap support

* no CSS maps when inline

Co-authored-by: Jason Miller <[email protected]>

Co-authored-by: Jason Miller <[email protected]>

Author: stipsan

src/index.js

@@ -447,6 +447,7 @@ function createConfig(options, entry, format, writeMeta) {
 						inject: false,
 						extract: options.css !== 'inline',
 						minimize: options.compress,
+						sourceMap: options.sourcemap && options.css !== 'inline',
 					}),
 					moduleAliases.length > 0 &&
 						alias({

test/__snapshots__/index.test.js.snap

@@ -433,6 +433,7 @@ Directory tree:
 basic-css
   dist
     basic-css.css
+    basic-css.css.map
     basic-css.esm.js
     basic-css.esm.js.map
     basic-css.js
@@ -454,9 +455,12 @@ Build \\"basicCss\\" to dist:
 138 B: basic-css.umd.js.br"
 `;
 
-exports[`fixtures build basic-css with microbundle 2`] = `7`;
+exports[`fixtures build basic-css with microbundle 2`] = `8`;
 
-exports[`fixtures build basic-css with microbundle 3`] = `".testing{display:flex;color:red;background:#00f}"`;
+exports[`fixtures build basic-css with microbundle 3`] = `
+".testing{display:flex;color:red;background:#00f}
+/*# sourceMappingURL=basic-css.css.map */"
+`;
 
 exports[`fixtures build basic-css with microbundle 4`] = `
 "function e(){var e=document.createElement(\\"div\\");return e.className=\\"testing\\",e}export default e;