Update to Rollup 2.

 - Update Rollup to 2.28.2. Fixes #821, closes #545
 - Update @rollup/plugin-commonjs. Upgrading this required Rollup 2 without any note in the changelog.  Closes #727
 - Update @rollup/plugin-json to 4.1.0. v4.0.3 is the first to add Rollup 2 in the peerDep range. Older versions are forward-compatible but will produce a peerDep warning
 - Update @rollup/plugin-replace to 2.3.3. v2.3.2 is the first version to add Rollup 2 in the peerDep range.
 - Update rollup-plugin-terser to v7. v6 requires rollup 2 and Node 10+. v7 introduces Terser 5, requires Node >= 10 and supports some new JS syntax. fixes #803, #fixes 797, closes #731
 - Update rollup-plugin-postcss to 3.1. Closes #693.
 - Remove sourcemap option from terser rollup plugin config, as of rollup-plugin-terser v6.0, it’s inferred automatically from Rollup’s output.source config.

package.json

@@ -48,10 +48,10 @@
     "@babel/preset-env": "^7.11.0",
     "@babel/traverse": "^7.11.5",
     "@rollup/plugin-babel": "^5.1.0",
-    "@rollup/plugin-commonjs": "^11.0.0",
-    "@rollup/plugin-json": "^4.0.0",
+    "@rollup/plugin-commonjs": "^15.1.0",
+    "@rollup/plugin-json": "^4.1.0",
     "@rollup/plugin-node-resolve": "^9.0.0",
-    "@rollup/plugin-replace": "^2.2.1",
+    "@rollup/plugin-replace": "^2.3.3",
     "@types/jest": "^25.2.1",
     "@typescript-eslint/eslint-plugin": "^2.12.0",
     "@typescript-eslint/parser": "^2.12.0",
@@ -86,9 +86,9 @@
     "prettier": "^1.19.1",
     "progress-estimator": "^0.2.2",
     "regenerator-runtime": "^0.13.7",
-    "rollup": "^1.32.1",
+    "rollup": "^2.28.2",
     "rollup-plugin-sourcemaps": "^0.6.2",
-    "rollup-plugin-terser": "^5.1.2",
+    "rollup-plugin-terser": "^7.0.2",
     "rollup-plugin-typescript2": "^0.26.0",
     "sade": "^1.4.2",
     "semver": "^7.1.1",
@@ -118,7 +118,7 @@
     "react": "^16.8.6",
     "react-dom": "^16.13.0",
     "react-is": "^16.13.0",
-    "rollup-plugin-postcss": "^2.5.0",
+    "rollup-plugin-postcss": "^3.1.8",
     "styled-components": "^5.0.1",
     "tiny-invariant": "^1.1.0",
     "tiny-warning": "^1.0.3",

src/createRollupConfig.ts

@@ -202,7 +202,6 @@ export async function createRollupConfig(
       sourceMaps(),
       shouldMinify &&
         terser({
-          sourcemap: true,
           output: { comments: false },
           compress: {
             keep_infinity: true,