remove deprecated

[jodinathan]

Fixed all files.
Exception from the material_input_multiline.dart at:

// TODO(google): remove after the bug is fixed.
          ..detectChanges();

As I don't know what bug it is talking about.

[jodinathan]

fixes #12

[GZGavinZhao]

@jodinathan I'm not sure if you can see the details of the workflow run, but if you can, please fix the little formatting. You can simply run dart format . in the top level directory and it will format everything for you. Thanks!

[GZGavinZhao]

So far this looks good:

grinder running analyze

analyze
  Counting number of Dart files...
  Analyzing...
  100% Done!
  1 out of 298 files are still using deprecated API!
- [ ] material_input/material_input_multiline.dart

finished in 6.8 seconds

Just waiting for the CI to run one more time to make sure nothing breaks during the build.

[jodinathan]

fixed #24