Remove unneeded dart_style dep, remove dep overrides... (#74)

Use latest setup-dart version
Test on oldest supported Dart SDK
Fix formatting
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 36f49c2..5c127a1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,10 +20,10 @@
     strategy:
       fail-fast: false
       matrix:
-        sdk: [dev, beta]
+        sdk: [dev, 2.12.0]
     steps:
       - uses: actions/checkout@v2
-      - uses: dart-lang/setup-dart@v0.5
+      - uses: dart-lang/setup-dart@v1.0
         with:
           sdk: ${{ matrix.sdk }}
       - id: install
@@ -47,10 +47,10 @@
       matrix:
         # Add macos-latest and/or windows-latest if relevant for this package.
         os: [ubuntu-latest]
-        sdk: [dev, beta]
+        sdk: [dev, 2.12.0]
     steps:
       - uses: actions/checkout@v2
-      - uses: dart-lang/setup-dart@v0.5
+      - uses: dart-lang/setup-dart@v1.0
         with:
           sdk: ${{ matrix.sdk }}
       - id: install
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 01610a2..1e86f5a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,5 @@
+## 1.0.1-dev
+
 ## 1.0.0
 
 * Migrate this package to null-safety
diff --git a/pubspec.yaml b/pubspec.yaml
index 3410339..b2963b8 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,11 +2,11 @@
 description: >-
   Utilities for the Dart VM Runtime including support for ANSI colors,
   file copying, and standard exit code values.
-version: 1.0.0
+version: 1.0.1-dev
 repository: https://github.com/dart-lang/io
 
 environment:
-  sdk: ">=2.12.0-0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   meta: ^1.3.0
@@ -14,12 +14,6 @@
   string_scanner: ^1.1.0
 
 dev_dependencies:
-  dart_style: ^1.0.7
   pedantic: ^1.10.0
   test: ^1.16.0
   test_descriptor: ^2.0.0
-
-dependency_overrides:
-  # Necessary until the test package supports 0.4.0
-  test: ^1.16.0
-  test_core: ^0.3.0
diff --git a/test/copy_path_test.dart b/test/copy_path_test.dart
index 612a516..57150fe 100644
--- a/test/copy_path_test.dart
+++ b/test/copy_path_test.dart
@@ -34,10 +34,10 @@
 }
 
 d.DirectoryDescriptor _struct() => d.dir('parent', [
-    d.dir('child', [
-      d.file('foo.txt'),
-    ]),
-  ]);
+      d.dir('child', [
+        d.file('foo.txt'),
+      ]),
+    ]);
 
 Future<void> _create() => _struct().create();
 Future<void> _validate() => _struct().validate();