build: round payload size for comparison

In some cases the payload is still showing up in the CI even if there was no change to the library. This seems to be because the file sizes are not rounded and can sometimes be not very exact. Resulting in numbers like: `material_fesm_2014": 1004.1319999999998`.

To have a more readable output in the gulp task, the file sizes should be rounded. This also makes the diff comparsion in the Firebase function better.

Author: devversion

tools/gulp/tasks/payload.ts

@@ -55,10 +55,12 @@ task('payload', ['material:clean-build'], async () => {
   }
 });
 
-/** Returns the size of the given library bundle. */
+/** Returns the size of the given library bundle. Size is rounded to two decimals places. */
 function getBundleSize(bundleName: string) {
-  return glob(bundleName, {cwd: bundlesDir})
+  const fileSize = glob(bundleName, {cwd: bundlesDir})
       .reduce((sum, fileName) => sum + getFilesize(join(bundlesDir, fileName)), 0);
+
+  return Math.round(fileSize * 100) / 100;
 }
 
 /** Returns the size of a file in kilobytes. */