chore: migrate from deprecated api

[dkrutskikh]

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix
[ ] New rule
[ ] Changes an existing rule
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

What changes did you make? (Give an overview)

Is there anything you'd like reviewers to focus on?

[codecov]

Codecov Report

Merging #581 (dcbd4ce) into master (f35888e) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #581   +/-   ##
=======================================
  Coverage   85.93%   85.93%           
=======================================
  Files         229      229           
  Lines        4863     4863           
=======================================
  Hits         4179     4179           
  Misses        684      684           

Impacted Files	Coverage Δ
lib/src/analyzer_plugin/analyzer_plugin_utils.dart	70.37% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f35888e...dcbd4ce. Read the comment docs.