Prepare Version 2.2.0

Author: konstantinullrich

.github/workflows/publish.yml

@@ -15,7 +15,7 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Publish package
-        uses: k-paxian/dart-package-publisher@v1.2
+        uses: k-paxian/dart-package-publisher@v1.6
         with:
           accessToken: ${{ secrets.GOOGLE_OAUTH_ACCESS_TOKEN }}
-          refreshToken: ${{ secrets.GOOGLE_OAUTH_REFRESH_TOKEN }}
+          refreshToken: ${{ secrets.GOOGLE_OAUTH_REFRESH_TOKEN }}

pubspec.yaml

@@ -6,7 +6,7 @@ repository: https://github.com/konstantinullrich/crypton
 issue_tracker: https://github.com/konstantinullrich/crypton/issues
 
 environment:
-  sdk: '>=2.14.0 <4.0.0'
+  sdk: '>=2.18.0 <4.0.0'
 
 dependencies:
   pointycastle: ^3.7.3