0.3.0-nullsafety

• Migrated package to null-safety.
• breaking change According to our unit tests, the API should be backwards-compatible. Some relevant changes were made, however:
  • Web: lastModified returns the epoch time as a default value, to maintain the Future<DateTime> return type (and not null)

0.2.1

• Prepare for breaking package:http change.

0.2.0

• breaking change Make sure the saveTo method returns a Future so it can be awaited and users are sure the file has been written to disk.

0.1.0+2

• Fix outdated links across a number of markdown files (#3276)

0.1.0+1

• Update Flutter SDK constraint.

0.1.0

• Initial open-source release.