Move to pkg:lints, small tweak to dependency constraints in pubspec (#62)

Also, dart format
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2d5753..ae26139 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,5 @@
+# 2.1.1-dev
+
 # 2.1.0
 - Added `Version.canonicalizedVersion` to help scrub leading zeros and highlight
   that `Version.toString()` preserves leading zeros.
diff --git a/analysis_options.yaml b/analysis_options.yaml
index d73e804..a5aacab 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -1,4 +1,4 @@
-include: package:pedantic/analysis_options.yaml
+include: package:lints/recommended.yaml
 
 analyzer:
   strong-mode:
diff --git a/lib/src/version_range.dart b/lib/src/version_range.dart
index a2a6327..9431b09 100644
--- a/lib/src/version_range.dart
+++ b/lib/src/version_range.dart
@@ -432,7 +432,9 @@
 
     final min = this.min;
     if (min != null) {
-      buffer..write(includeMin ? '>=' : '>')..write(min);
+      buffer
+        ..write(includeMin ? '>=' : '>')
+        ..write(min);
     }
 
     final max = this.max;
@@ -440,7 +442,9 @@
     if (max != null) {
       if (min != null) buffer.write(' ');
       if (includeMax) {
-        buffer..write('<=')..write(max);
+        buffer
+          ..write('<=')
+          ..write(max);
       } else {
         buffer.write('<');
         if (max.isFirstPreRelease) {
diff --git a/pubspec.yaml b/pubspec.yaml
index 214f0cd..ca45a9e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,16 +1,17 @@
 name: pub_semver
-version: 2.1.0
+version: 2.1.1-dev
 description: >-
  Versions and version constraints implementing pub's versioning policy. This
  is very similar to vanilla semver, with a few corner cases.
 repository: https://github.com/dart-lang/pub_semver
 
 environment:
- sdk: '>=2.12.0-0 <3.0.0'
+ sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   collection: ^1.15.0
   meta: ^1.3.0
 
 dev_dependencies:
-  test: ^1.16.0-nullsafety.1
+  lints: ^1.0.0
+  test: ^1.16.0