add README.md

LICENSE

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+MIT License
+
+Copyright 2022 Ryota Sasazawa.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+## Slack Notice AWS Support
+
+Notify slack of AWS support case with subject, status, submittedby, timecreated and url. It requires setting up [aws-actions/configure-aws-credentials](https://github.com/marketplace/actions/configure-aws-credentials-action-for-github-actions) and activating [Imcomming Webhooks](https://api.slack.com/messaging/webhooks).
+
+## Usage
+Configure aws credentials before using this action.
+
+```yaml
+on:
+  schedule:
+    - cron: '0 1 * * 1-5'
+
+permissions:
+  id-token: write
+  contents: write
+
+jobs:
+  notify-slack-aws-support:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Git clone the repository
+        uses: actions/checkout@v1
+
+      - name: Configure aws credentials
+        uses: aws-actions/configure-aws-credentials@master
+        with:
+          role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role
+          aws-region: ap-northeast-1
+
+      - name:  Notify slack of aws support
+        uses: sasamuku/slack_notice_aws_support@main
+        with:
+          include_resolved_cases: 'false'
+          language: 'ja'
+          webhook_url: 'http://hooks.slack.com/services/...'
+```
+
+See [action.yml](action.yml) for the full documentation for this action's inputs and outputs.
+
+## AWS Credentials
+
+The credentials used in GitHub Actions workflows must have permissions to [DescribeCases](https://docs.aws.amazon.com/awssupport/latest/APIReference/API_DescribeCases.html).
+
+```yaml
+    - Effect: 'Allow'
+      Action:
+        - 'support:DescribeCases'
+      Resource: '*'
+```
+
+See [Access permissions for AWS Support](https://docs.aws.amazon.com/awssupport/latest/user/accessing-support.html) for more details.
+
+## Imcomming webhooks
+Activate [Incoming Webhooks](https://api.slack.com/messaging/webhooks) ant get the url similar to the following:
+```
+http://hooks.slack.com/services/...
+```
+
+## License Summary
+This code is made available under the MIT license.

action.yml

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 name: 'Slack Notice AWS Support'
-description: 'Notify slack of AWS support case with subject, status, submitteby and url'
+description: 'Notify slack of AWS support case with subject, status, submittedby, timecreated and url'
 author: 'sasamuku'
 inputs:
   include_resolved_cases: