Add notes regarding migrating from pedantic (#41)

Author: srawlins

README.md

@@ -64,6 +64,19 @@ You can customize the pre-defined lint sets, both to disable one or more of the
 lints included, or to add additional lints. For details see [customizing static
 analysis].
 
+## Migrating from `package:pedantic`
+
+In migrating from the pre-defined lint sets provided by the [`package:pedantic`],
+you get static analysis coverage from 29 additional lints.  There are, however,
+6 lints which the pedantic package includes which are not included in the
+pre-defined lint sets provided by the lints package:
+`always_declare_return_types`, `prefer_single_quotes`,
+`sort_child_properties_last` (included in [`package:flutter_lints`]),
+`unawaited_futures`, `unsafe_html`, and
+`use_full_hex_values_for_flutter_colors` (included in [`package:flutter_lints`]).
+To keep any of these lints enabled,
+add them to your [analysis options][customizing static analysis].
+
 ## Submitting Feedback
 
 Feedback is welcome! If you want to propose an existing lint for inclusion here,
@@ -79,3 +92,5 @@ lints or have an idea for a new one, please file an issue on the [linter repo].
 [pub.dev]: https://pub.dev
 [issue]: https://github.com/dart-lang/lints/issues
 [linter repo]: https://github.com/dart-lang/linter
+[`package:pedantic`]: https://pub.dev/packages/pedantic
+[`package:flutter_lints`]: https://pub.dev/packages/flutter_lints